implement JS-only Taler, remove emscripten

23 files changed, 575 insertions, 2636 deletions

diff --git a/src/crypto/browserWorkerEntry.ts b/src/crypto/browserWorkerEntry.ts
index d133e93cc..5ac762c13 100644
--- a/src/crypto/browserWorkerEntry.ts
+++ b/src/crypto/browserWorkerEntry.ts
@@ -23,61 +23,11 @@
  */
 
 import { CryptoImplementation } from "./cryptoImplementation";
-import { EmscEnvironment } from "./emscInterface";
 
 const worker: Worker = (self as any) as Worker;
 
-class BrowserEmscriptenLoader {
-  private cachedEmscEnvironment: EmscEnvironment | undefined = undefined;
-  private cachedEmscEnvironmentPromise:
-    | Promise<EmscEnvironment>
-    | undefined = undefined;
-
-  async getEmscriptenEnvironment(): Promise<EmscEnvironment> {
-
-    if (this.cachedEmscEnvironment) {
-      return this.cachedEmscEnvironment;
-    }
-
-    if (this.cachedEmscEnvironmentPromise) {
-      return this.cachedEmscEnvironmentPromise;
-    }
-
-    console.log("loading emscripten lib with 'importScripts'");
-    // @ts-ignore
-    self.TalerEmscriptenLib = {};
-    // @ts-ignore
-    importScripts('/emscripten/taler-emscripten-lib.js')
-    // @ts-ignore
-    if (!self.TalerEmscriptenLib) {
-      throw Error("can't import taler emscripten lib");
-    }
-    const locateFile = (path: string, scriptDir: string) => {
-      console.log("locating file", "path", path, "scriptDir", scriptDir);
-      // This is quite hacky and assumes that our scriptDir is dist/
-      return scriptDir + "../emscripten/" + path;
-    };
-    console.log("instantiating TalerEmscriptenLib");
-    // @ts-ignore
-    const lib = self.TalerEmscriptenLib({ locateFile });
-    return new Promise((resolve, reject) => {
-      lib.then((mod: any) => {
-        this.cachedEmscEnvironmentPromise = undefined;
-        const emsc = new EmscEnvironment(mod);
-        this.cachedEmscEnvironment = new EmscEnvironment(mod);
-        console.log("emscripten module fully loaded");
-        resolve(emsc);
-      });
-    });
-  }
-}
-
-let loader = new BrowserEmscriptenLoader();
-
 async function handleRequest(operation: string, id: number, args: string[]) {
-  let emsc = await loader.getEmscriptenEnvironment();
-
-  const impl = new CryptoImplementation(emsc);
+  const impl = new CryptoImplementation();
 
   if (!(operation in impl)) {
     console.error(`crypto operation '${operation}' not found`);
diff --git a/src/crypto/cryptoApi-test.ts b/src/crypto/cryptoApi-test.ts
deleted file mode 100644
index d9d42081c..000000000
--- a/src/crypto/cryptoApi-test.ts
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- This file is part of TALER
- (C) 2017 Inria and GNUnet e.V.
-
- TALER is free software; you can redistribute it and/or modify it under the
- terms of the GNU General Public License as published by the Free Software
- Foundation; either version 3, or (at your option) any later version.
-
- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along with
- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-// tslint:disable:max-line-length
-
-import test from "ava";
-
-import {
-  DenominationRecord,
-  DenominationStatus,
-  ReserveRecord,
-  ReserveRecordStatus,
-} from "../dbTypes";
-
-import { CryptoApi } from "./cryptoApi";
-import { NodeCryptoWorkerFactory } from "./nodeProcessWorker";
-
-const masterPub1: string =
-  "CQQZ9DY3MZ1ARMN5K1VKDETS04Y2QCKMMCFHZSWJWWVN82BTTH00";
-
-const denomValid1: DenominationRecord = {
-  denomPub:
-    "51R7ARKCD5HJTTV5F4G0M818E9SP280A40G2GVH04CR30GHS84R3JHHP6GSM2D9Q6514CGT568R32C9J6CWM4DSH64TM4DSM851K0CA48CVKAC1P6H144C2160T46DHK8CVM4HJ274S38C1M6S338D9N6GWM8DT684T3JCT36S13EC9G88R3EGHQ8S0KJGSQ60SKGD216N33AGJ2651K2E9S60TMCD1N75244HHQ6X33EDJ570R3GGJ2651MACA38D130DA560VK4HHJ68WK2CA26GW3ECSH6D13EC9S88VK2GT66WVK8D9G750K0D9R8RRK4DHQ71332GHK8D23GE26710M2H9K6WVK8HJ38MVKEGA66N23AC9H88VKACT58MV3CCSJ6H1K4DT38GRK0C9M8N33CE1R60V4AHA38H1KECSH6S33JH9N8GRKGH1K68S36GH354520818CMG26C1H60R30C935452081918G2J2G0",
-  denomPubHash: "dummy",
-  exchangeBaseUrl: "https://exchange.example.com/",
-  feeDeposit: {
-    currency: "PUDOS",
-    fraction: 10000,
-    value: 0,
-  },
-  feeRefresh: {
-    currency: "PUDOS",
-    fraction: 10000,
-    value: 0,
-  },
-  feeRefund: {
-    currency: "PUDOS",
-    fraction: 10000,
-    value: 0,
-  },
-  feeWithdraw: {
-    currency: "PUDOS",
-    fraction: 10000,
-    value: 0,
-  },
-  isOffered: true,
-  masterSig:
-    "CJFJCQ48Q45PSGJ5KY94N6M2TPARESM2E15BSPBD95YVVPEARAEQ6V6G4Z2XBMS0QM0F3Y9EYVP276FCS90EQ1578ZC8JHFBZ3NGP3G",
-  stampExpireDeposit: "/Date(1851580381)/",
-  stampExpireLegal: "/Date(1567756381)/",
-  stampExpireWithdraw: "/Date(2482300381)/",
-  stampStart: "/Date(1473148381)/",
-  status: DenominationStatus.Unverified,
-  value: {
-    currency: "PUDOS",
-    fraction: 100000,
-    value: 0,
-  },
-};
-
-const denomInvalid1 = JSON.parse(JSON.stringify(denomValid1));
-denomInvalid1.value.value += 1;
-
-test("string hashing", async t => {
-  const crypto = new CryptoApi(new NodeCryptoWorkerFactory());
-  const s = await crypto.hashString("hello taler");
-  const sh =
-    "8RDMADB3YNF3QZBS3V467YZVJAMC2QAQX0TZGVZ6Q5PFRRAJFT70HHN0QF661QR9QWKYMMC7YEMPD679D2RADXCYK8Y669A2A5MKQFR";
-  t.true(s === sh);
-  t.pass();
-});
-
-test("precoin creation", async t => {
-  const crypto = new CryptoApi(new NodeCryptoWorkerFactory());
-  const { priv, pub } = await crypto.createEddsaKeypair();
-  const r: ReserveRecord = {
-    created: { t_ms: 0 },
-    currentAmount: null,
-    exchangeBaseUrl: "https://example.com/exchange",
-    hasPayback: false,
-    precoinAmount: { currency: "PUDOS", value: 0, fraction: 0 },
-    requestedAmount: { currency: "PUDOS", value: 0, fraction: 0 },
-    reservePriv: priv,
-    reservePub: pub,
-    timestampConfirmed: undefined,
-    timestampReserveInfoPosted: undefined,
-    exchangeWire: "payto://foo",
-    reserveStatus: ReserveRecordStatus.UNCONFIRMED,
-  };
-
-  const precoin = await crypto.createPreCoin(denomValid1, r);
-  t.truthy(precoin);
-  t.pass();
-});
-
-test("denom validation", async t => {
-  const crypto = new CryptoApi(new NodeCryptoWorkerFactory());
-  let v: boolean;
-  v = await crypto.isValidDenom(denomValid1, masterPub1);
-  t.true(v);
-  v = await crypto.isValidDenom(denomInvalid1, masterPub1);
-  t.true(!v);
-  t.pass();
-});
diff --git a/src/crypto/cryptoImplementation.ts b/src/crypto/cryptoImplementation.ts
index 38c63ceee..9ffdec701 100644
--- a/src/crypto/cryptoImplementation.ts
+++ b/src/crypto/cryptoImplementation.ts
@@ -14,10 +14,9 @@
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
-
 /**
  * Synchronous implementation of crypto-related functions for the wallet.
- * 
+ *
  * The functionality is parameterized over an Emscripten environment.
  */
 
@@ -38,19 +37,118 @@ import {
 } from "../dbTypes";
 
 import { CoinPaySig, ContractTerms, PaybackRequest } from "../talerTypes";
-import { BenchmarkResult, CoinWithDenom, PayCoinInfo } from "../walletTypes";
-import { canonicalJson } from "../helpers";
-import { EmscEnvironment } from "./emscInterface";
-import * as native from "./emscInterface";
+import {
+  BenchmarkResult,
+  CoinWithDenom,
+  PayCoinInfo,
+  Timestamp,
+} from "../walletTypes";
+import { canonicalJson, getTalerStampSec } from "../helpers";
 import { AmountJson } from "../amounts";
 import * as Amounts from "../amounts";
 import * as timer from "../timer";
-import { getRandomBytes, encodeCrock } from "./talerCrypto";
+import {
+  getRandomBytes,
+  encodeCrock,
+  decodeCrock,
+  createEddsaKeyPair,
+  createBlindingKeySecret,
+  hash,
+  rsaBlind,
+  eddsaVerify,
+  eddsaSign,
+  rsaUnblind,
+  stringToBytes,
+  createHashContext,
+  createEcdheKeyPair,
+  keyExchangeEcdheEddsa,
+  setupRefreshPlanchet,
+} from "./talerCrypto";
+import { randomBytes } from "./primitives/nacl-fast";
+
+enum SignaturePurpose {
+  RESERVE_WITHDRAW = 1200,
+  WALLET_COIN_DEPOSIT = 1201,
+  MASTER_DENOMINATION_KEY_VALIDITY = 1025,
+  WALLET_COIN_MELT = 1202,
+  TEST = 4242,
+  MERCHANT_PAYMENT_OK = 1104,
+  MASTER_WIRE_FEES = 1028,
+  WALLET_COIN_PAYBACK = 1203,
+  WALLET_COIN_LINK = 1204,
+}
+
+function amountToBuffer(amount: AmountJson): Uint8Array {
+  const buffer = new ArrayBuffer(8 + 4 + 12);
+  const dvbuf = new DataView(buffer);
+  const u8buf = new Uint8Array(buffer);
+  const te = new TextEncoder();
+  const curr = te.encode(amount.currency);
+  dvbuf.setBigUint64(0, BigInt(amount.value));
+  dvbuf.setUint32(8, amount.fraction);
+  u8buf.set(curr, 8 + 4);
+
+  return u8buf;
+}
+
+function timestampToBuffer(ts: Timestamp): Uint8Array {
+  const b = new ArrayBuffer(8);
+  const v = new DataView(b);
+  const s = BigInt(ts.t_ms) * BigInt(1000);
+  v.setBigUint64(0, s);
+  return new Uint8Array(b);
+}
+
+function talerTimestampStringToBuffer(ts: string): Uint8Array {
+  const t_sec = getTalerStampSec(ts);
+  if (t_sec === null || t_sec === undefined) {
+    // Should have been validated before!
+    throw Error("invalid timestamp");
+  }
+  const buffer = new ArrayBuffer(8);
+  const dvbuf = new DataView(buffer);
+  const s = BigInt(t_sec) * BigInt(1000 * 1000);
+  dvbuf.setBigUint64(0, s);
+  return new Uint8Array(buffer);
+}
+
+class SignaturePurposeBuilder {
+  private chunks: Uint8Array[] = [];
+
+  constructor(private purposeNum: number) {}
+
+  put(bytes: Uint8Array): SignaturePurposeBuilder {
+    this.chunks.push(Uint8Array.from(bytes));
+    return this;
+  }
+
+  build(): Uint8Array {
+    let payloadLen = 0;
+    for (let c of this.chunks) {
+      payloadLen += c.byteLength;
+    }
+    const buf = new ArrayBuffer(4 + 4 + payloadLen);
+    const u8buf = new Uint8Array(buf);
+    let p = 8;
+    for (let c of this.chunks) {
+      u8buf.set(c, p);
+      p += c.byteLength;
+    }
+    const dvbuf = new DataView(buf);
+    dvbuf.setUint32(0, payloadLen + 4 + 4);
+    dvbuf.setUint32(4, this.purposeNum);
+    return u8buf;
+  }
+}
+
+function buildSigPS(purposeNum: number): SignaturePurposeBuilder {
+  return new SignaturePurposeBuilder(purposeNum);
+}
 
 export class CryptoImplementation {
   static enableTracing: boolean = false;
 
-  constructor(private emsc: EmscEnvironment) {}
+  constructor() {}
 
   /**
    * Create a pre-coin of the given denomination to be withdrawn from then given
@@ -60,54 +158,39 @@ export class CryptoImplementation {
     denom: DenominationRecord,
     reserve: ReserveRecord,
   ): PreCoinRecord {
-    const reservePriv = new native.EddsaPrivateKey(this.emsc);
-    reservePriv.loadCrock(reserve.reservePriv);
-    const reservePub = new native.EddsaPublicKey(this.emsc);
-    reservePub.loadCrock(reserve.reservePub);
-    const denomPub = native.RsaPublicKey.fromCrock(this.emsc, denom.denomPub);
-    const coinPriv = native.EddsaPrivateKey.create(this.emsc);
-    const coinPub = coinPriv.getPublicKey();
-    const blindingFactor = native.RsaBlindingKeySecret.create(this.emsc);
-    const pubHash: native.HashCode = coinPub.hash();
-    const ev = native.rsaBlind(pubHash, blindingFactor, denomPub);
-
-    if (!ev) {
-      throw Error("couldn't blind (malicious exchange key?)");
-    }
-
-    if (!denom.feeWithdraw) {
-      throw Error("Field fee_withdraw missing");
-    }
-
-    const amountWithFee = new native.Amount(this.emsc, denom.value);
-    amountWithFee.add(new native.Amount(this.emsc, denom.feeWithdraw));
-    const withdrawFee = new native.Amount(this.emsc, denom.feeWithdraw);
-
-    const denomPubHash = denomPub.encode().hash();
-
-    // Signature
-    const withdrawRequest = new native.WithdrawRequestPS(this.emsc, {
-      amount_with_fee: amountWithFee.toNbo(),
-      h_coin_envelope: ev.hash(),
-      h_denomination_pub: denomPubHash,
-      reserve_pub: reservePub,
-      withdraw_fee: withdrawFee.toNbo(),
-    });
-
-    const sig = native.eddsaSign(withdrawRequest.toPurpose(), reservePriv);
+    const reservePub = decodeCrock(reserve.reservePub);
+    const reservePriv = decodeCrock(reserve.reservePriv);
+    const denomPub = decodeCrock(denom.denomPub);
+    const coinKeyPair = createEddsaKeyPair();
+    const blindingFactor = createBlindingKeySecret();
+    const coinPubHash = hash(coinKeyPair.eddsaPub);
+    const ev = rsaBlind(coinPubHash, blindingFactor, denomPub);
+    const amountWithFee = Amounts.add(denom.value, denom.feeWithdraw).amount;
+    const denomPubHash = hash(denomPub);
+    const evHash = hash(ev);
+
+    const withdrawRequest = buildSigPS(SignaturePurpose.RESERVE_WITHDRAW)
+      .put(reservePub)
+      .put(amountToBuffer(amountWithFee))
+      .put(amountToBuffer(denom.feeWithdraw))
+      .put(denomPubHash)
+      .put(evHash)
+      .build();
+
+    const sig = eddsaSign(withdrawRequest, reservePriv);
 
     const preCoin: PreCoinRecord = {
-      blindingKey: blindingFactor.toCrock(),
-      coinEv: ev.toCrock(),
-      coinPriv: coinPriv.toCrock(),
-      coinPub: coinPub.toCrock(),
+      blindingKey: encodeCrock(blindingFactor),
+      coinEv: encodeCrock(ev),
+      coinPriv: encodeCrock(coinKeyPair.eddsaPriv),
+      coinPub: encodeCrock(coinKeyPair.eddsaPub),
       coinValue: denom.value,
-      denomPub: denomPub.toCrock(),
-      denomPubHash: denomPubHash.toCrock(),
+      denomPub: encodeCrock(denomPub),
+      denomPubHash: encodeCrock(denomPubHash),
       exchangeBaseUrl: reserve.exchangeBaseUrl,
       isFromTip: false,
-      reservePub: reservePub.toCrock(),
-      withdrawSig: sig.toCrock(),
+      reservePub: encodeCrock(reservePub),
+      withdrawSig: encodeCrock(sig),
     };
     return preCoin;
   }
@@ -116,32 +199,20 @@ export class CryptoImplementation {
    * Create a planchet used for tipping, including the private keys.
    */
   createTipPlanchet(denom: DenominationRecord): TipPlanchet {
-    const denomPub = native.RsaPublicKey.fromCrock(this.emsc, denom.denomPub);
-    const coinPriv = native.EddsaPrivateKey.create(this.emsc);
-    const coinPub = coinPriv.getPublicKey();
-    const blindingFactor = native.RsaBlindingKeySecret.create(this.emsc);
-    const pubHash: native.HashCode = coinPub.hash();
-    const ev = native.rsaBlind(pubHash, blindingFactor, denomPub);
-
-    if (!ev) {
-      throw Error("couldn't blind (malicious exchange key?)");
-    }
-
-    if (!denom.feeWithdraw) {
-      throw Error("Field fee_withdraw missing");
-    }
+    const denomPub = decodeCrock(denom.denomPub);
+    const coinKeyPair = createEddsaKeyPair();
+    const blindingFactor = createBlindingKeySecret();
+    const coinPubHash = hash(coinKeyPair.eddsaPub);
+    const ev = rsaBlind(coinPubHash, blindingFactor, denomPub);
 
     const tipPlanchet: TipPlanchet = {
-      blindingKey: blindingFactor.toCrock(),
-      coinEv: ev.toCrock(),
-      coinPriv: coinPriv.toCrock(),
-      coinPub: coinPub.toCrock(),
+      blindingKey: encodeCrock(blindingFactor),
+      coinEv: encodeCrock(ev),
+      coinPriv: encodeCrock(coinKeyPair.eddsaPriv),
+      coinPub: encodeCrock(coinKeyPair.eddsaPub),
       coinValue: denom.value,
-      denomPub: denomPub.encode().toCrock(),
-      denomPubHash: denomPub
-        .encode()
-        .hash()
-        .toCrock(),
+      denomPub: encodeCrock(denomPub),
+      denomPubHash: encodeCrock(hash(denomPub)),
     };
     return tipPlanchet;
   }
@@ -150,22 +221,18 @@ export class CryptoImplementation {
    * Create and sign a message to request payback for a coin.
    */
   createPaybackRequest(coin: CoinRecord): PaybackRequest {
-    const p = new native.PaybackRequestPS(this.emsc, {
-      coin_blind: native.RsaBlindingKeySecret.fromCrock(
-        this.emsc,
-        coin.blindingKey,
-      ),
-      coin_pub: native.EddsaPublicKey.fromCrock(this.emsc, coin.coinPub),
-      h_denom_pub: native.RsaPublicKey.fromCrock(this.emsc, coin.denomPub)
-        .encode()
-        .hash(),
-    });
-    const coinPriv = native.EddsaPrivateKey.fromCrock(this.emsc, coin.coinPriv);
-    const coinSig = native.eddsaSign(p.toPurpose(), coinPriv);
+    const p = buildSigPS(SignaturePurpose.WALLET_COIN_PAYBACK)
+      .put(decodeCrock(coin.coinPub))
+      .put(decodeCrock(coin.denomPubHash))
+      .put(decodeCrock(coin.blindingKey))
+      .build();
+
+    const coinPriv = decodeCrock(coin.coinPriv);
+    const coinSig = eddsaSign(p, coinPriv);
     const paybackRequest: PaybackRequest = {
       coin_blind_key_secret: coin.blindingKey,
       coin_pub: coin.coinPub,
-      coin_sig: coinSig.toCrock(),
+      coin_sig: encodeCrock(coinSig),
       denom_pub: coin.denomPub,
       denom_sig: coin.denomSig,
     };
@@ -180,114 +247,72 @@ export class CryptoImplementation {
     contractHash: string,
     merchantPub: string,
   ): boolean {
-    const p = new native.PaymentSignaturePS(this.emsc, {
-      contract_hash: native.HashCode.fromCrock(this.emsc, contractHash),
-    });
-    const nativeSig = new native.EddsaSignature(this.emsc);
-    nativeSig.loadCrock(sig);
-    const nativePub = native.EddsaPublicKey.fromCrock(this.emsc, merchantPub);
-    return native.eddsaVerify(
-      native.SignaturePurpose.MERCHANT_PAYMENT_OK,
-      p.toPurpose(),
-      nativeSig,
-      nativePub,
-    );
+    const p = buildSigPS(SignaturePurpose.MERCHANT_PAYMENT_OK)
+      .put(decodeCrock(contractHash))
+      .build();
+    const sigBytes = decodeCrock(sig);
+    const pubBytes = decodeCrock(merchantPub);
+    return eddsaVerify(p, sigBytes, pubBytes);
   }
 
   /**
    * Check if a wire fee is correctly signed.
    */
   isValidWireFee(type: string, wf: WireFee, masterPub: string): boolean {
-    const p = new native.MasterWireFeePS(this.emsc, {
-      closing_fee: new native.Amount(this.emsc, wf.closingFee).toNbo(),
-      end_date: native.AbsoluteTimeNbo.fromStampSeconds(this.emsc, (wf.endStamp.t_ms / 1000)),
-      h_wire_method: native.ByteArray.fromStringWithNull(
-        this.emsc,
-        type,
-      ).hash(),
-      start_date: native.AbsoluteTimeNbo.fromStampSeconds(
-        this.emsc,
-        Math.floor(wf.startStamp.t_ms / 1000),
-      ),
-      wire_fee: new native.Amount(this.emsc, wf.wireFee).toNbo(),
-    });
-
-    const nativeSig = new native.EddsaSignature(this.emsc);
-    nativeSig.loadCrock(wf.sig);
-    const nativePub = native.EddsaPublicKey.fromCrock(this.emsc, masterPub);
-
-    return native.eddsaVerify(
-      native.SignaturePurpose.MASTER_WIRE_FEES,
-      p.toPurpose(),
-      nativeSig,
-      nativePub,
-    );
+    const p = buildSigPS(SignaturePurpose.MASTER_WIRE_FEES)
+      .put(hash(stringToBytes(type + "\0")))
+      .put(timestampToBuffer(wf.startStamp))
+      .put(timestampToBuffer(wf.endStamp))
+      .put(amountToBuffer(wf.wireFee))
+      .build();
+    const sig = decodeCrock(wf.sig);
+    const pub = decodeCrock(masterPub);
+    return eddsaVerify(p, sig, pub);
   }
 
   /**
    * Check if the signature of a denomination is valid.
    */
   isValidDenom(denom: DenominationRecord, masterPub: string): boolean {
-    const p = new native.DenominationKeyValidityPS(this.emsc, {
-      denom_hash: native.RsaPublicKey.fromCrock(this.emsc, denom.denomPub)
-        .encode()
-        .hash(),
-      expire_legal: native.AbsoluteTimeNbo.fromTalerString(
-        this.emsc,
-        denom.stampExpireLegal,
-      ),
-      expire_spend: native.AbsoluteTimeNbo.fromTalerString(
-        this.emsc,
-        denom.stampExpireDeposit,
-      ),
-      expire_withdraw: native.AbsoluteTimeNbo.fromTalerString(
-        this.emsc,
-        denom.stampExpireWithdraw,
-      ),
-      fee_deposit: new native.Amount(this.emsc, denom.feeDeposit).toNbo(),
-      fee_refresh: new native.Amount(this.emsc, denom.feeRefresh).toNbo(),
-      fee_refund: new native.Amount(this.emsc, denom.feeRefund).toNbo(),
-      fee_withdraw: new native.Amount(this.emsc, denom.feeWithdraw).toNbo(),
-      master: native.EddsaPublicKey.fromCrock(this.emsc, masterPub),
-      start: native.AbsoluteTimeNbo.fromTalerString(
-        this.emsc,
-        denom.stampStart,
-      ),
-      value: new native.Amount(this.emsc, denom.value).toNbo(),
-    });
-
-    const nativeSig = new native.EddsaSignature(this.emsc);
-    nativeSig.loadCrock(denom.masterSig);
-
-    const nativePub = native.EddsaPublicKey.fromCrock(this.emsc, masterPub);
-
-    return native.eddsaVerify(
-      native.SignaturePurpose.MASTER_DENOMINATION_KEY_VALIDITY,
-      p.toPurpose(),
-      nativeSig,
-      nativePub,
-    );
+    const p = buildSigPS(SignaturePurpose.MASTER_DENOMINATION_KEY_VALIDITY)
+      .put(decodeCrock(masterPub))
+      .put(timestampToBuffer(denom.stampStart))
+      .put(timestampToBuffer(denom.stampExpireWithdraw))
+      .put(timestampToBuffer(denom.stampExpireDeposit))
+      .put(timestampToBuffer(denom.stampExpireLegal))
+      .put(amountToBuffer(denom.value))
+      .put(amountToBuffer(denom.feeWithdraw))
+      .put(amountToBuffer(denom.feeDeposit))
+      .put(amountToBuffer(denom.feeRefresh))
+      .put(amountToBuffer(denom.feeRefund))
+      .put(decodeCrock(denom.denomPubHash))
+      .build();
+    const sig = decodeCrock(denom.masterSig);
+    const pub = decodeCrock(masterPub);
+    return eddsaVerify(p, sig, pub);
   }
 
   /**
    * Create a new EdDSA key pair.
    */
   createEddsaKeypair(): { priv: string; pub: string } {
-    const priv = native.EddsaPrivateKey.create(this.emsc);
-    const pub = priv.getPublicKey();
-    return { priv: priv.toCrock(), pub: pub.toCrock() };
+    const pair = createEddsaKeyPair();
+    return {
+      priv: encodeCrock(pair.eddsaPriv),
+      pub: encodeCrock(pair.eddsaPub),
+    };
   }
 
   /**
    * Unblind a blindly signed value.
    */
   rsaUnblind(sig: string, bk: string, pk: string): string {
-    const denomSig = native.rsaUnblind(
-      native.RsaSignature.fromCrock(this.emsc, sig),
-      native.RsaBlindingKeySecret.fromCrock(this.emsc, bk),
-      native.RsaPublicKey.fromCrock(this.emsc, pk),
+    const denomSig = rsaUnblind(
+      decodeCrock(sig),
+      decodeCrock(pk),
+      decodeCrock(bk),
     );
-    return denomSig.encode().toCrock();
+    return encodeCrock(denomSig);
   }
 
   /**
@@ -315,79 +340,54 @@ export class CryptoImplementation {
       .amount;
     const total = Amounts.add(fees, totalAmount).amount;
 
-    const amountSpent = native.Amount.getZero(
-      this.emsc,
-      cds[0].coin.currentAmount.currency,
-    );
-    const amountRemaining = new native.Amount(this.emsc, total);
+    let amountSpent = Amounts.getZero(cds[0].coin.currentAmount.currency);
+    let amountRemaining = total;
+
     for (const cd of cds) {
-      let coinSpend: native.Amount;
       const originalCoin = { ...cd.coin };
 
       if (amountRemaining.value === 0 && amountRemaining.fraction === 0) {
         break;
       }
 
-      if (
-        amountRemaining.cmp(
-          new native.Amount(this.emsc, cd.coin.currentAmount),
-        ) < 0
-      ) {
-        coinSpend = new native.Amount(this.emsc, amountRemaining.toJson());
+      let coinSpend: AmountJson;
+      if (Amounts.cmp(amountRemaining, cd.coin.currentAmount) < 0) {
+        coinSpend = amountRemaining;
       } else {
-        coinSpend = new native.Amount(this.emsc, cd.coin.currentAmount);
+        coinSpend = cd.coin.currentAmount;
       }
 
-      amountSpent.add(coinSpend);
-      amountRemaining.sub(coinSpend);
+      amountSpent = Amounts.add(amountSpent, coinSpend).amount;
 
-      const feeDeposit: native.Amount = new native.Amount(
-        this.emsc,
-        cd.denom.feeDeposit,
-      );
+      const feeDeposit = cd.denom.feeDeposit;
 
       // Give the merchant at least the deposit fee, otherwise it'll reject
       // the coin.
-      if (coinSpend.cmp(feeDeposit) < 0) {
+
+      if (Amounts.cmp(coinSpend, feeDeposit) < 0) {
         coinSpend = feeDeposit;
       }
 
-      const newAmount = new native.Amount(this.emsc, cd.coin.currentAmount);
-      newAmount.sub(coinSpend);
-      cd.coin.currentAmount = newAmount.toJson();
+      const newAmount = Amounts.sub(cd.coin.currentAmount, coinSpend).amount;
+      cd.coin.currentAmount = newAmount;
       cd.coin.status = CoinStatus.Dirty;
 
-      const d = new native.DepositRequestPS(this.emsc, {
-        amount_with_fee: coinSpend.toNbo(),
-        coin_pub: native.EddsaPublicKey.fromCrock(this.emsc, cd.coin.coinPub),
-        deposit_fee: new native.Amount(this.emsc, cd.denom.feeDeposit).toNbo(),
-        h_contract: native.HashCode.fromCrock(this.emsc, contractTermsHash),
-        h_wire: native.HashCode.fromCrock(this.emsc, contractTerms.H_wire),
-        merchant: native.EddsaPublicKey.fromCrock(
-          this.emsc,
-          contractTerms.merchant_pub,
-        ),
-        refund_deadline: native.AbsoluteTimeNbo.fromTalerString(
-          this.emsc,
-          contractTerms.refund_deadline,
-        ),
-        timestamp: native.AbsoluteTimeNbo.fromTalerString(
-          this.emsc,
-          contractTerms.timestamp,
-        ),
-      });
-
-      const coinSig = native
-        .eddsaSign(
-          d.toPurpose(),
-          native.EddsaPrivateKey.fromCrock(this.emsc, cd.coin.coinPriv),
-        )
-        .toCrock();
+      const d = buildSigPS(SignaturePurpose.WALLET_COIN_DEPOSIT)
+        .put(decodeCrock(contractTermsHash))
+        .put(decodeCrock(contractTerms.H_wire))
+        .put(talerTimestampStringToBuffer(contractTerms.timestamp))
+        .put(talerTimestampStringToBuffer(contractTerms.refund_deadline))
+        .put(amountToBuffer(coinSpend))
+        .put(amountToBuffer(cd.denom.feeDeposit))
+        .put(decodeCrock(contractTerms.merchant_pub))
+        .put(decodeCrock(cd.coin.coinPub))
+        .build();
+      const coinSig = eddsaSign(d, decodeCrock(cd.coin.coinPriv));
 
       const s: CoinPaySig = {
         coin_pub: cd.coin.coinPub,
-        coin_sig: coinSig,
-        contribution: Amounts.toString(coinSpend.toJson()),
+        coin_sig: encodeCrock(coinSig),
+        contribution: Amounts.toString(coinSpend),
         denom_pub: cd.coin.denomPub,
         exchange_url: cd.denom.exchangeBaseUrl,
         ub_sig: cd.coin.denomSig,
@@ -419,7 +419,7 @@ export class CryptoImplementation {
     // melt fee
     valueWithFee = Amounts.add(valueWithFee, meltFee).amount;
 
-    const sessionHc = new native.HashContext(this.emsc);
+    const sessionHc = createHashContext();
 
     const transferPubs: string[] = [];
     const transferPrivs: string[] = [];
@@ -427,79 +427,57 @@ export class CryptoImplementation {
     const preCoinsForGammas: RefreshPreCoinRecord[][] = [];
 
     for (let i = 0; i < kappa; i++) {
-      const t = native.EcdhePrivateKey.create(this.emsc);
-      const pub = t.getPublicKey();
-      sessionHc.read(pub);
-      transferPrivs.push(t.toCrock());
-      transferPubs.push(pub.toCrock());
+      const transferKeyPair = createEcdheKeyPair();
+      sessionHc.update(transferKeyPair.ecdhePub);
+      transferPrivs.push(encodeCrock(transferKeyPair.ecdhePriv));
+      transferPubs.push(encodeCrock(transferKeyPair.ecdhePub));
     }
 
     for (const denom of newCoinDenoms) {
-      const r = native.RsaPublicKey.fromCrock(this.emsc, denom.denomPub);
-      sessionHc.read(r.encode());
+      const r = decodeCrock(denom.denomPub);
+      sessionHc.update(r);
     }
 
-    sessionHc.read(
-      native.EddsaPublicKey.fromCrock(this.emsc, meltCoin.coinPub),
-    );
-    sessionHc.read(new native.Amount(this.emsc, valueWithFee).toNbo());
+    sessionHc.update(decodeCrock(meltCoin.coinPub));
+    sessionHc.update(amountToBuffer(valueWithFee));
 
     for (let i = 0; i < kappa; i++) {
       const preCoins: RefreshPreCoinRecord[] = [];
       for (let j = 0; j < newCoinDenoms.length; j++) {
-        const transferPriv = native.EcdhePrivateKey.fromCrock(
-          this.emsc,
-          transferPrivs[i],
-        );
-        const oldCoinPub = native.EddsaPublicKey.fromCrock(
-          this.emsc,
-          meltCoin.coinPub,
-        );
-        const transferSecret = native.ecdhEddsa(transferPriv, oldCoinPub);
-
-        const fresh = native.setupFreshCoin(transferSecret, j);
-
-        const coinPriv = fresh.priv;
-        const coinPub = coinPriv.getPublicKey();
-        const blindingFactor = fresh.blindingKey;
-        const pubHash: native.HashCode = coinPub.hash();
-        const denomPub = native.RsaPublicKey.fromCrock(
-          this.emsc,
-          newCoinDenoms[j].denomPub,
-        );
-        const ev = native.rsaBlind(pubHash, blindingFactor, denomPub);
-        if (!ev) {
-          throw Error("couldn't blind (malicious exchange key?)");
-        }
+        const transferPriv = decodeCrock(transferPrivs[i]);
+        const oldCoinPub = decodeCrock(meltCoin.coinPub);
+        const transferSecret = keyExchangeEcdheEddsa(transferPriv, oldCoinPub);
+
+        const fresh = setupRefreshPlanchet(transferSecret, j);
+
+        const coinPriv = fresh.coinPriv;
+        const coinPub = fresh.coinPub;
+        const blindingFactor = fresh.bks;
+        const pubHash = hash(coinPub);
+        const denomPub = decodeCrock(newCoinDenoms[j].denomPub);
+        const ev = rsaBlind(pubHash, blindingFactor, denomPub);
         const preCoin: RefreshPreCoinRecord = {
-          blindingKey: blindingFactor.toCrock(),
-          coinEv: ev.toCrock(),
-          privateKey: coinPriv.toCrock(),
-          publicKey: coinPub.toCrock(),
+          blindingKey: encodeCrock(blindingFactor),
+          coinEv: encodeCrock(ev),
+          privateKey: encodeCrock(coinPriv),
+          publicKey: encodeCrock(coinPub),
         };
         preCoins.push(preCoin);
-        sessionHc.read(ev);
+        sessionHc.update(ev);
       }
       preCoinsForGammas.push(preCoins);
     }
 
-    const sessionHash = new native.HashCode(this.emsc);
-    sessionHash.alloc();
-    sessionHc.finish(sessionHash);
+    const sessionHash = sessionHc.finish();
 
-    const confirmData = new native.RefreshMeltCoinAffirmationPS(this.emsc, {
-      amount_with_fee: new native.Amount(this.emsc, valueWithFee).toNbo(),
-      coin_pub: native.EddsaPublicKey.fromCrock(this.emsc, meltCoin.coinPub),
-      melt_fee: new native.Amount(this.emsc, meltFee).toNbo(),
-      session_hash: sessionHash,
-    });
+    const confirmData = buildSigPS(SignaturePurpose.WALLET_COIN_MELT)
+      .put(sessionHash)
+      .put(amountToBuffer(valueWithFee))
+      .put(amountToBuffer(meltFee))
+      .put(decodeCrock(meltCoin.coinPub))
+      .build();
 
-    const confirmSig: string = native
-      .eddsaSign(
-        confirmData.toPurpose(),
-        native.EddsaPrivateKey.fromCrock(this.emsc, meltCoin.coinPriv),
-      )
-      .toCrock();
+    const confirmSig = eddsaSign(confirmData, decodeCrock(meltCoin.coinPriv));
 
     let valueOutput = Amounts.getZero(newCoinDenoms[0].value.currency);
     for (const denom of newCoinDenoms) {
@@ -510,10 +488,10 @@ export class CryptoImplementation {
 
     const refreshSession: RefreshSessionRecord = {
       refreshSessionId,
-      confirmSig,
+      confirmSig: encodeCrock(confirmSig),
       exchangeBaseUrl,
       finished: false,
-      hash: sessionHash.toCrock(),
+      hash: encodeCrock(sessionHash),
       meltCoinPub: meltCoin.coinPub,
       newDenomHashes: newCoinDenoms.map(d => d.denomPubHash),
       newDenoms: newCoinDenoms.map(d => d.denomPub),
@@ -532,18 +510,16 @@ export class CryptoImplementation {
    * Hash a string including the zero terminator.
    */
   hashString(str: string): string {
-    const b = native.ByteArray.fromStringWithNull(this.emsc, str);
-    return b.hash().toCrock();
+    const ts = new TextEncoder();
+    const b = ts.encode(str + "\0");
+    return encodeCrock(hash(b));
   }
 
   /**
    * Hash a denomination public key.
    */
   hashDenomPub(denomPub: string): string {
-    return native.RsaPublicKey.fromCrock(this.emsc, denomPub)
-      .encode()
-      .hash()
-      .toCrock();
+    return encodeCrock(hash(decodeCrock(denomPub)));
   }
 
   signCoinLink(
@@ -553,20 +529,16 @@ export class CryptoImplementation {
     transferPub: string,
     coinEv: string,
   ): string {
-    const coinEvHash = native.ByteArray.fromCrock(this.emsc, coinEv).hash();
-
-    const coinLink = new native.CoinLinkSignaturePS(this.emsc, {
-      coin_envelope_hash: coinEvHash,
-      h_denom_pub: native.HashCode.fromCrock(this.emsc, newDenomHash),
-      old_coin_pub: native.EddsaPublicKey.fromCrock(this.emsc, oldCoinPub),
-      transfer_pub: native.EcdhePublicKey.fromCrock(this.emsc, transferPub),
-    });
-
-    const coinPriv = native.EddsaPrivateKey.fromCrock(this.emsc, oldCoinPriv);
-
-    const sig = native.eddsaSign(coinLink.toPurpose(), coinPriv);
-
-    return sig.toCrock();
+    const coinEvHash = hash(decodeCrock(coinEv));
+    const coinLink = buildSigPS(SignaturePurpose.WALLET_COIN_LINK)
+      .put(decodeCrock(newDenomHash))
+      .put(decodeCrock(oldCoinPub))
+      .put(decodeCrock(transferPub))
+      .put(coinEvHash)
+      .build();
+    const coinPriv = decodeCrock(oldCoinPriv);
+    const sig = eddsaSign(coinLink, coinPriv);
+    return encodeCrock(sig);
   }
 
   benchmark(repetitions: number): BenchmarkResult {
@@ -578,165 +550,40 @@ export class CryptoImplementation {
     }
 
     let time_hash_big = 0;
-    const ba = new native.ByteArray(this.emsc, 4096);
     for (let i = 0; i < repetitions; i++) {
-      ba.randomize(native.RandomQuality.WEAK);
+      const ba = randomBytes(4096);
       const start = timer.performanceNow();
-      ba.hash();
+      hash(ba);
       time_hash_big += timer.performanceNow() - start;
     }
 
     let time_eddsa_create = 0;
     for (let i = 0; i < repetitions; i++) {
       const start = timer.performanceNow();
-      const priv: native.EddsaPrivateKey = native.EddsaPrivateKey.create(
-        this.emsc,
-      );
+      const pair = createEddsaKeyPair();
       time_eddsa_create += timer.performanceNow() - start;
-      priv.destroy();
     }
 
     let time_eddsa_sign = 0;
-    const eddsaPriv: native.EddsaPrivateKey = native.EddsaPrivateKey.create(
-      this.emsc,
-    );
-    const eddsaPub: native.EddsaPublicKey = eddsaPriv.getPublicKey();
-    const h: native.HashCode = new native.HashCode(this.emsc);
-    h.alloc();
-    h.random(native.RandomQuality.WEAK);
+    const p = randomBytes(4096);
 
-    const ps = new native.PaymentSignaturePS(this.emsc, {
-      contract_hash: h,
-    });
-
-    const p = ps.toPurpose();
+    const pair = createEddsaKeyPair();
 
     for (let i = 0; i < repetitions; i++) {
       const start = timer.performanceNow();
-      native.eddsaSign(p, eddsaPriv);
+      eddsaSign(p, pair.eddsaPriv);
       time_eddsa_sign += timer.performanceNow() - start;
     }
 
-    const eddsaSig = native.eddsaSign(p, eddsaPriv);
-
-    let time_ecdsa_create = 0;
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      const priv: native.EcdsaPrivateKey = native.EcdsaPrivateKey.create(
-        this.emsc,
-      );
-      time_ecdsa_create += timer.performanceNow() - start;
-      priv.destroy();
-    }
+    const sig = eddsaSign(p, pair.eddsaPriv);
 
     let time_eddsa_verify = 0;
     for (let i = 0; i < repetitions; i++) {
       const start = timer.performanceNow();
-      native.eddsaVerify(
-        native.SignaturePurpose.MERCHANT_PAYMENT_OK,
-        p,
-        eddsaSig,
-        eddsaPub,
-      );
+      eddsaVerify(p, sig, pair.eddsaPub);
       time_eddsa_verify += timer.performanceNow() - start;
     }
 
-    /* rsa 2048 */
-
-    let time_rsa_2048_blind = 0;
-    const rsaPriv2048: native.RsaPrivateKey = native.RsaPrivateKey.create(
-      this.emsc,
-      2048,
-    );
-    const rsaPub2048 = rsaPriv2048.getPublicKey();
-    const blindingSecret2048 = native.RsaBlindingKeySecret.create(this.emsc);
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaBlind(h, blindingSecret2048, rsaPub2048);
-      time_rsa_2048_blind += timer.performanceNow() - start;
-    }
-
-    const blindedMessage2048 = native.rsaBlind(
-      h,
-      blindingSecret2048,
-      rsaPub2048,
-    );
-    if (!blindedMessage2048) {
-      throw Error("should not happen");
-    }
-    const rsaBlindSig2048 = native.rsaSignBlinded(
-      rsaPriv2048,
-      blindedMessage2048,
-    );
-
-    let time_rsa_2048_unblind = 0;
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaUnblind(rsaBlindSig2048, blindingSecret2048, rsaPub2048);
-      time_rsa_2048_unblind += timer.performanceNow() - start;
-    }
-
-    const unblindedSig2048 = native.rsaUnblind(
-      rsaBlindSig2048,
-      blindingSecret2048,
-      rsaPub2048,
-    );
-
-    let time_rsa_2048_verify = 0;
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaVerify(h, unblindedSig2048, rsaPub2048);
-      time_rsa_2048_verify += timer.performanceNow() - start;
-    }
-
-    /* rsa 4096 */
-
-    let time_rsa_4096_blind = 0;
-    const rsaPriv4096: native.RsaPrivateKey = native.RsaPrivateKey.create(
-      this.emsc,
-      4096,
-    );
-    const rsaPub4096 = rsaPriv4096.getPublicKey();
-    const blindingSecret4096 = native.RsaBlindingKeySecret.create(this.emsc);
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaBlind(h, blindingSecret4096, rsaPub4096);
-      time_rsa_4096_blind += timer.performanceNow() - start;
-    }
-
-    const blindedMessage4096 = native.rsaBlind(
-      h,
-      blindingSecret4096,
-      rsaPub4096,
-    );
-    if (!blindedMessage4096) {
-      throw Error("should not happen");
-    }
-    const rsaBlindSig4096 = native.rsaSignBlinded(
-      rsaPriv4096,
-      blindedMessage4096,
-    );
-
-    let time_rsa_4096_unblind = 0;
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaUnblind(rsaBlindSig4096, blindingSecret4096, rsaPub4096);
-      time_rsa_4096_unblind += timer.performanceNow() - start;
-    }
-
-    const unblindedSig4096 = native.rsaUnblind(
-      rsaBlindSig4096,
-      blindingSecret4096,
-      rsaPub4096,
-    );
-
-    let time_rsa_4096_verify = 0;
-    for (let i = 0; i < repetitions; i++) {
-      const start = timer.performanceNow();
-      native.rsaVerify(h, unblindedSig4096, rsaPub4096);
-      time_rsa_4096_verify += timer.performanceNow() - start;
-    }
-
     return {
       repetitions,
       time: {
@@ -745,13 +592,6 @@ export class CryptoImplementation {
         eddsa_create: time_eddsa_create,
         eddsa_sign: time_eddsa_sign,
         eddsa_verify: time_eddsa_verify,
-        ecdsa_create: time_ecdsa_create,
-        rsa_2048_blind: time_rsa_2048_blind,
-        rsa_2048_unblind: time_rsa_2048_unblind,
-        rsa_2048_verify: time_rsa_2048_verify,
-        rsa_4096_blind: time_rsa_4096_blind,
-        rsa_4096_unblind: time_rsa_4096_unblind,
-        rsa_4096_verify: time_rsa_4096_verify,
       },
     };
   }
diff --git a/src/crypto/emscInterface-test.ts b/src/crypto/emscInterface-test.ts
deleted file mode 100644
index 30b9c2b51..000000000
--- a/src/crypto/emscInterface-test.ts
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- This file is part of TALER
- (C) 2017 Inria and GNUnet e.V.
-
- TALER is free software; you can redistribute it and/or modify it under the
- terms of the GNU General Public License as published by the Free Software
- Foundation; either version 3, or (at your option) any later version.
-
- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along with
- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-// tslint:disable:max-line-length
-
-import test from "ava";
-import { NodeEmscriptenLoader } from "./nodeEmscriptenLoader";
-import * as native from "./emscInterface";
-
-import { encodeCrock, decodeCrock } from "./talerCrypto";
-import { timestampCheck } from "../helpers";
-
-
-test("string hashing", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const x = native.ByteArray.fromStringWithNull(emsc, "hello taler");
-  const h = "8RDMADB3YNF3QZBS3V467YZVJAMC2QAQX0TZGVZ6Q5PFRRAJFT70HHN0QF661QR9QWKYMMC7YEMPD679D2RADXCYK8Y669A2A5MKQFR";
-  const hc = x.hash().toCrock();
-  console.log(`# hc ${hc}`);
-  t.true(h === hc, "must equal");
-
-  const te = new TextEncoder();
-
-  const x2 = te.encode("hello taler\0");
-
-  t.pass();
-});
-
-
-test("signing", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const x = native.ByteArray.fromStringWithNull(emsc, "hello taler");
-  const priv = native.EddsaPrivateKey.create(emsc);
-  const pub = priv.getPublicKey();
-  const purpose = new native.EccSignaturePurpose(emsc, native.SignaturePurpose.TEST, x);
-
-  const purposeDataCrock = purpose.toCrock();
-  const privCrock = priv.toCrock();
-  const pubCrock = pub.toCrock();
-  const sig = native.eddsaSign(purpose, priv);
-  console.time("a");
-  for (let i = 0; i < 5000; i++) {
-    const sig = native.eddsaSign(purpose, priv);
-  }
-  console.timeEnd("a");
-  t.true(native.eddsaVerify(native.SignaturePurpose.TEST, purpose, sig, pub));
-
-  const d2 = new Uint8Array(decodeCrock(purposeDataCrock));
-  console.log("sig1:", sig.toCrock());
-
-  t.pass();
-});
-
-
-test("signing-fixed-data", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const x = native.ByteArray.fromStringWithNull(emsc, "hello taler");
-  const purpose = new native.EccSignaturePurpose(emsc, native.SignaturePurpose.TEST, x);
-  const privStr = "G9R8KRRCAFKPD0KW7PW48CC2T03VQ8K2AN9J6J6K2YW27J5MHN90";
-  const pubStr = "YHCZB442FQFJ0ET20MWA8YJ53M61EZGJ6QKV1KTJZMRNXDY45WT0";
-  const sigStr = "7V6XY4QGC1406GPMT305MZQ1HDCR7R0S5BP02GTGDQFPSXB6YD2YDN5ZS7NJQCNP61Y39MRHXNXQ1Z15JY4CJY4CPDA6CKQ3313WG38";
-  const priv = native.EddsaPrivateKey.fromCrock(emsc, privStr);
-  t.true(privStr === priv.toCrock());
-  const pub = priv.getPublicKey();
-  t.true(pubStr === pub.toCrock());
-  const sig = native.EddsaSignature.fromCrock(emsc, sigStr);
-  t.true(sigStr === sig.toCrock());
-  const sig2 = native.eddsaSign(purpose, priv);
-  t.true(sig.toCrock() === sig2.toCrock());
-  t.true(native.eddsaVerify(native.SignaturePurpose.TEST, purpose, sig, pub));
-  t.pass();
-});
-
-
-const denomPubStr1 = "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";
-
-
-test("rsa-encode", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const pubHashStr = "JM63YM5X7X547164QJ3MGJZ4WDD47GEQR5DW5SH35G4JFZXEJBHE5JBNZM5K8XN5C4BRW25BE6GSVAYBF790G2BZZ13VW91D41S4DS0";
-  const denomPub = native.RsaPublicKey.fromCrock(emsc, denomPubStr1);
-  const pubHash = denomPub.encode().hash();
-  t.true(pubHashStr === pubHash.toCrock());
-  t.pass();
-});
-
-
-test("withdraw-request", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const reservePrivStr = "G9R8KRRCAFKPD0KW7PW48CC2T03VQ8K2AN9J6J6K2YW27J5MHN90";
-  const reservePriv = native.EddsaPrivateKey.fromCrock(emsc, reservePrivStr);
-  const reservePub = reservePriv.getPublicKey();
-  const amountWithFee = new native.Amount(emsc, {currency: "KUDOS", value: 1, fraction: 10000});
-  amountWithFee.add(new native.Amount(emsc, {currency: "KUDOS", value: 0, fraction: 20000}));
-  const withdrawFee = new native.Amount(emsc, {currency: "KUDOS", value: 0, fraction: 20000});
-  const denomPub = native.RsaPublicKey.fromCrock(emsc, denomPubStr1);
-  const ev = native.ByteArray.fromStringWithNull(emsc, "hello, world");
-
-  // Signature
-  const withdrawRequest = new native.WithdrawRequestPS(emsc, {
-    amount_with_fee: amountWithFee.toNbo(),
-    h_coin_envelope: ev.hash(),
-    h_denomination_pub: denomPub.encode().hash(),
-    reserve_pub: reservePub,
-    withdraw_fee: withdrawFee.toNbo(),
-  });
-
-  const sigStr = "AD3T8W44NV193J19RAN3NAJHPP6RVB0R3NWV7ZK5G8Q946YDK0B6F8YJBNRRBXSPVTKY31S7BVZPJFFTJJRMY61DH51X4JSXK677428";
-
-  const sig = native.eddsaSign(withdrawRequest.toPurpose(), reservePriv);
-  t.true(native.eddsaVerify(native.SignaturePurpose.RESERVE_WITHDRAW, withdrawRequest.toPurpose(), sig, reservePub));
-  t.true(sig.toCrock() === sigStr);
-  t.pass();
-});
-
-
-test("currency-conversion", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const a1 = new native.Amount(emsc, {currency: "KUDOS", value: 1, fraction: 50000000});
-  const a2 = new native.Amount(emsc, {currency: "KUDOS", value: 1, fraction: 50000000});
-  a1.add(a2);
-  const x = a1.toJson();
-  t.true(x.currency === "KUDOS");
-  t.true(x.fraction === 0);
-  t.true(x.value === 3);
-  t.pass();
-});
-
-
-test("ecdsa", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const priv = native.EcdsaPrivateKey.create(emsc);
-  const pub1 = priv.getPublicKey();
-  t.truthy(priv);
-  t.truthy(pub1);
-  t.pass();
-});
-
-
-test("ecdhe", async (t) => {
-  const loader =  new NodeEmscriptenLoader();
-  const emsc = await loader.getEmscriptenEnvironment();
-
-  const priv = native.EcdhePrivateKey.create(emsc);
-  const pub = priv.getPublicKey();
-  t.truthy(priv);
-  t.truthy(pub);
-  t.pass();
-});
diff --git a/src/crypto/emscInterface.ts b/src/crypto/emscInterface.ts
deleted file mode 100644
index da5442a61..000000000
--- a/src/crypto/emscInterface.ts
+++ /dev/null
@@ -1,1657 +0,0 @@
-/*
- This file is part of TALER
- (C) 2015 GNUnet e.V.
-
- TALER is free software; you can redistribute it and/or modify it under the
- terms of the GNU General Public License as published by the Free Software
- Foundation; either version 3, or (at your option) any later version.
-
- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along with
- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-
-/**
- * Medium-level interface to emscripten-compiled modules used
- * by the wallet.  Handles memory management by allocating by allocating
- * objects in arenas that then can be disposed of all at once.
- *
- * The high-level interface (using WebWorkers) is exposed in src/cryptoApi.ts.
- */
-
-/**
- * Imports.
- */
-import { AmountJson } from "../amounts";
-
-/**
- * Size of a native pointer.  Must match the size
- * use when compiling via emscripten.
- */
-const PTR_SIZE = 4;
-
-const GNUNET_OK = 1;
-
-
-/**
- * Signature of the function that retrieves emscripten
- * function implementations.
- */
-export interface EmscFunGen {
-  (name: string,
-   ret: string,
-   args: string[]): ((...x: Array<number|string>) => any);
-  (name: string,
-   ret: "number",
-   args: string[]): ((...x: Array<number|string>) => number);
-  (name: string,
-   ret: "void",
-   args: string[]): ((...x: Array<number|string>) => void);
-  (name: string,
-   ret: "string",
-   args: string[]): ((...x: Array<number|string>) => string);
-}
-
-
-interface EmscLib {
-  cwrap: EmscFunGen;
-
-  ccall(name: string, ret: "number"|"string", argTypes: any[], args: any[]): any;
-
-  stringToUTF8(s: string, addr: number, maxLength: number): void;
-
-  onRuntimeInitialized(f: () => void): void;
-
-  readBinary?: (filename: string) => Promise<ArrayBuffer>;
-
-  calledRun?: boolean;
-
-  _free(ptr: number): void;
-
-  _malloc(n: number): number;
-
-  UTF8ToString(p: number, len?: number): string;
-
-  getValue(ptr: number, type: string, noSafe?: boolean): number;
-
-  setValue(ptr: number, value: number, type: string, noSafe?: boolean): void;
-
-  writeStringToMemory(s: string, buffer: number, dontAddNull?: boolean): void;
-}
-
-interface EmscFunctions {
-  amount_add(a1: number, a2: number, a3: number): number;
-  amount_cmp(a1: number, a2: number): number;
-  amount_get_zero(a1: string, a2: number): number;
-  amount_hton(a1: number, a2: number): void;
-  amount_normalize(a1: number): void;
-  amount_ntoh(a1: number, a2: number): void;
-  amount_subtract(a1: number, a2: number, a3: number): number;
-  ecdh_eddsa(a1: number, a2: number, a3: number): number;
-  eddsa_sign(a1: number, a2: number, a3: number): number;
-  eddsa_verify(a1: number, a2: number, a3: number, a4: number): number;
-  free(ptr: number): void;
-  get_currency(a: number): string;
-  get_fraction(a: number): number;
-  get_value(a: number): number;
-  hash(a1: number, a2: number, a3: number): void;
-  hash_context_abort(ctx: number): void;
-  hash_context_finish(a1: number, a2: number): void;
-  hash_context_read(a1: number, a2: number, a3: number): void;
-  hash_create_random(a1: number, a2: number): void;
-  memmove(a1: number, a2: number, a3: number): number;
-  random_block(a1: number, a2: number, a3: number): void;
-  rsa_blinding_key_free(a1: number): void;
-  rsa_public_key_free(a1: number): void;
-  rsa_private_key_free(a1: number): void;
-  rsa_signature_free(a1: number): void;
-  rsa_verify(msgHash: number, sig: number, pubKey: number): number;
-  setup_fresh_coin(a1: number, a2: number, a3: number): void;
-  string_to_data(a1: number, a2: number, a3: number, a4: number): number;
-}
-
-interface EmscAllocFunctions {
-  data_to_string_alloc(a1: number, a2: number): number;
-  ecdhe_key_create(): number;
-  ecdhe_public_key_from_private(a1: number): number;
-  ecdsa_key_create(): number;
-  ecdsa_public_key_from_private(a1: number): number;
-  eddsa_key_create(): number;
-  eddsa_public_key_from_private(a1: number): number;
-  /**
-   * Note that value_1 and value_2 are the first 64-bit parameter,
-   * and not two separate parameters (by the emscripten calling convention).
-   */
-  get_amount(value_1: number, value_2: number, fraction: number, currency: string): number;
-  hash_context_start(): number;
-  malloc(size: number): number;
-  purpose_create(a1: number, a2: number, a3: number): number;
-  rsa_blind(a1: number, a2: number, a3: number, a4: number, a5: number): number;
-  rsa_blinding_key_create(a1: number): number;
-  rsa_blinding_key_decode(a1: number, a2: number): number;
-  rsa_blinding_key_encode(a1: number, a2: number): number;
-  rsa_private_key_create(len: number): number;
-  rsa_private_key_decode(a1: number, a2: number): number;
-  rsa_private_key_encode(a1: number, a2: number): number;
-  rsa_private_key_get_public(privKeyPtr: number): number;
-  rsa_public_key_decode(a1: number, a2: number): number;
-  rsa_public_key_encode(a1: number, a2: number): number;
-  rsa_signature_decode(a1: number, a2: number): number;
-  rsa_signature_encode(a1: number, a2: number): number;
-  rsa_sign_blinded(keyPtr: number, msgPtr: number, msgLen: number): number;
-  rsa_unblind(a1: number, a2: number, a3: number): number;
-}
-
-export class EmscEnvironment {
-
-  /**
-   * Emscripten functions that don't do any memory allocations.
-   */
-  public funcs: EmscFunctions;
-
-  /**
-   * Emscripten functions that allocate memory.
-   */
-  public allocFuncs: EmscAllocFunctions;
-
-  public lib: EmscLib;
-
-  constructor(lib: EmscLib) {
-    const getEmsc: EmscFunGen = (name: string, ret: any, argTypes: any[]) => {
-      return (...args: any[]) => {
-        return lib.ccall(name, ret, argTypes, args);
-      };
-    };
-    this.lib = lib;
-    this.allocFuncs = {
-      data_to_string_alloc: getEmsc("GNUNET_STRINGS_data_to_string_alloc", "number", ["number", "number"]),
-      ecdhe_key_create: getEmsc("GNUNET_CRYPTO_ecdhe_key_create", "number", []),
-      ecdhe_public_key_from_private: getEmsc( "TALER_WRALL_ecdhe_public_key_from_private", "number", ["number"]),
-      ecdsa_key_create: getEmsc("GNUNET_CRYPTO_ecdsa_key_create", "number", []),
-      ecdsa_public_key_from_private: getEmsc( "TALER_WRALL_ecdsa_public_key_from_private", "number", ["number"]),
-      eddsa_key_create: getEmsc("GNUNET_CRYPTO_eddsa_key_create", "number", []),
-      eddsa_public_key_from_private: getEmsc( "TALER_WRALL_eddsa_public_key_from_private", "number", ["number"]),
-      get_amount: getEmsc("TALER_WRALL_get_amount", "number", ["number", "number", "number", "string"]),
-      hash_context_start: getEmsc("GNUNET_CRYPTO_hash_context_start", "number", []),
-      malloc: (size: number) => lib._malloc(size),
-      purpose_create: getEmsc("TALER_WRALL_purpose_create", "number", ["number", "number", "number"]),
-      rsa_blind: getEmsc("GNUNET_CRYPTO_rsa_blind", "number", ["number", "number", "number", "number", "number"]),
-      rsa_blinding_key_create: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_create", "number", ["number"]),
-      rsa_blinding_key_decode: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_decode", "number", ["number", "number"]),
-      rsa_blinding_key_encode: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_encode", "number", ["number", "number"]),
-      rsa_private_key_create: getEmsc("GNUNET_CRYPTO_rsa_private_key_create", "number", ["number"]),
-      rsa_private_key_decode: getEmsc("GNUNET_CRYPTO_rsa_private_key_decode", "number", ["number", "number"]),
-      rsa_private_key_encode: getEmsc("GNUNET_CRYPTO_rsa_private_key_encode", "number", ["number", "number"]),
-      rsa_private_key_get_public: getEmsc("GNUNET_CRYPTO_rsa_private_key_get_public", "number", ["number"]),
-      rsa_public_key_decode: getEmsc("GNUNET_CRYPTO_rsa_public_key_decode", "number", ["number", "number"]),
-      rsa_public_key_encode: getEmsc("GNUNET_CRYPTO_rsa_public_key_encode", "number", ["number", "number"]),
-      rsa_signature_decode: getEmsc("GNUNET_CRYPTO_rsa_signature_decode", "number", ["number", "number"]),
-      rsa_signature_encode: getEmsc("GNUNET_CRYPTO_rsa_signature_encode", "number", ["number", "number"]),
-      rsa_sign_blinded: getEmsc("GNUNET_CRYPTO_rsa_sign_blinded", "number", ["number", "number", "number"]),
-      rsa_unblind: getEmsc("GNUNET_CRYPTO_rsa_unblind", "number", ["number", "number", "number"]),
-    };
-    this.funcs = {
-      amount_add: getEmsc("TALER_amount_add", "number", ["number", "number", "number"]),
-      amount_cmp: getEmsc("TALER_amount_cmp", "number", ["number", "number"]),
-      amount_get_zero: getEmsc("TALER_amount_get_zero", "number", ["string", "number"]),
-      amount_hton: getEmsc("TALER_amount_hton", "void", ["number", "number"]),
-      amount_normalize: getEmsc("TALER_amount_normalize", "void", ["number"]),
-      amount_ntoh: getEmsc("TALER_amount_ntoh", "void", ["number", "number"]),
-      amount_subtract: getEmsc("TALER_amount_subtract", "number", ["number", "number", "number"]),
-      ecdh_eddsa: getEmsc("GNUNET_CRYPTO_ecdh_eddsa", "number", ["number", "number", "number"]),
-      eddsa_sign: getEmsc("GNUNET_CRYPTO_eddsa_sign", "number", ["number", "number", "number"]),
-      eddsa_verify: getEmsc("GNUNET_CRYPTO_eddsa_verify", "number", ["number", "number", "number", "number"]),
-      free: (ptr: number) => lib._free(ptr),
-      get_currency: getEmsc("TALER_WR_get_currency", "string", ["number"]),
-      get_fraction: getEmsc("TALER_WR_get_fraction", "number", ["number"]),
-      get_value: getEmsc("TALER_WR_get_value", "number", ["number"]),
-      hash: getEmsc("GNUNET_CRYPTO_hash", "void", ["number", "number", "number"]),
-      hash_context_abort: getEmsc("GNUNET_CRYPTO_hash_context_abort", "void", ["number"]),
-      hash_context_finish: getEmsc("GNUNET_CRYPTO_hash_context_finish", "void", ["number", "number"]),
-      hash_context_read: getEmsc("GNUNET_CRYPTO_hash_context_read", "void", ["number", "number", "number"]),
-      hash_create_random: getEmsc("GNUNET_CRYPTO_hash_create_random", "void", ["number", "number"]),
-      memmove: getEmsc("memmove", "number", ["number", "number", "number"]),
-      random_block: getEmsc("GNUNET_CRYPTO_random_block", "void", ["number", "number", "number"]),
-      rsa_blinding_key_free: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_free", "void", ["number"]),
-      rsa_public_key_free: getEmsc("GNUNET_CRYPTO_rsa_public_key_free", "void", ["number"]),
-      rsa_private_key_free: getEmsc("GNUNET_CRYPTO_rsa_private_key_free", "void", ["number"]),
-      rsa_signature_free: getEmsc("GNUNET_CRYPTO_rsa_signature_free", "void", ["number"]),
-      rsa_verify: getEmsc("GNUNET_CRYPTO_rsa_verify", "number", ["number", "number", "number"]),
-      setup_fresh_coin: getEmsc("TALER_setup_fresh_coin", "void", ["number", "number", "number"]),
-      string_to_data: getEmsc("GNUNET_STRINGS_string_to_data", "number", ["number", "number", "number", "number"]),
-    };
-  }
-}
-
-
-/**
- * Constants for signatures purposes, define what the signatures vouches for.
- */
-export enum SignaturePurpose {
-  RESERVE_WITHDRAW = 1200,
-  WALLET_COIN_DEPOSIT = 1201,
-  MASTER_DENOMINATION_KEY_VALIDITY = 1025,
-  WALLET_COIN_MELT = 1202,
-  TEST = 4242,
-  MERCHANT_PAYMENT_OK = 1104,
-  MASTER_WIRE_FEES = 1028,
-  WALLET_COIN_PAYBACK = 1203,
-  WALLET_COIN_LINK = 1204,
-}
-
-
-/**
- * Desired quality levels for random numbers.
- */
-export enum RandomQuality {
-  WEAK = 0,
-  STRONG = 1,
-  NONCE = 2,
-}
-
-
-/**
- * Object that is allocated in some arena.
- */
-interface ArenaObject {
-  destroy(): void;
-}
-
-
-/**
- * Context for cummulative hashing.
- */
-export class HashContext implements ArenaObject {
-  private hashContextPtr: number | undefined;
-
-  constructor(private emsc: EmscEnvironment) {
-    this.hashContextPtr = emsc.allocFuncs.hash_context_start();
-  }
-
-  /**
-   * Add data to be hashed.
-   */
-  read(obj: PackedArenaObject): void {
-    if (!this.hashContextPtr) {
-      throw Error("assertion failed");
-    }
-    this.emsc.funcs.hash_context_read(this.hashContextPtr, obj.nativePtr, obj.size());
-  }
-
-  /**
-   * Finish the hash computation.
-   */
-  finish(h: HashCode) {
-    if (!this.hashContextPtr) {
-      throw Error("assertion failed");
-    }
-    h.alloc();
-    this.emsc.funcs.hash_context_finish(this.hashContextPtr, h.nativePtr);
-  }
-
-  /**
-   * Abort hashing without computing the result.
-   */
-  destroy(): void {
-    if (this.hashContextPtr) {
-      this.emsc.funcs.hash_context_abort(this.hashContextPtr);
-    }
-    this.hashContextPtr = undefined;
-  }
-}
-
-
-/**
- * Arena object that points to an allocated block of memory.
- */
-abstract class MallocArenaObject implements ArenaObject {
-  protected _nativePtr: number | undefined = undefined;
-
-  /**
-   * Is this a weak reference to the underlying memory?
-   */
-  isWeak = false;
-
-  destroy(): void {
-    if (this._nativePtr && !this.isWeak) {
-      this.emsc.funcs.free(this.nativePtr);
-      this._nativePtr = undefined;
-    }
-  }
-
-  constructor(public emsc: EmscEnvironment, arena?: Arena) {
-    if (!arena) {
-      if (arenaStack.length === 0) {
-        throw Error("No arena available");
-      }
-      arena = arenaStack[arenaStack.length - 1];
-    }
-    arena.put(this);
-  }
-
-  alloc(size: number) {
-    if (this._nativePtr !== undefined) {
-      throw Error("Double allocation");
-    }
-    this.nativePtr = this.emsc.allocFuncs.malloc(size);
-  }
-
-  set nativePtr(v: number) {
-    if (v === undefined) {
-      throw Error("Native pointer must be a number or null");
-    }
-    this._nativePtr = v;
-  }
-
-  get nativePtr() {
-    // We want to allow latent allocation
-    // of native wrappers, but we never want to
-    // pass 'undefined' to emscripten.
-    if (this._nativePtr === undefined) {
-      throw Error("Native pointer not initialized");
-    }
-    return this._nativePtr;
-  }
-}
-
-
-/**
- * An arena stores objects that will be deallocated
- * at the same time.
- */
-interface Arena {
-  put(obj: ArenaObject): void;
-  destroy(): void;
-}
-
-
-/**
- * Arena that must be manually destroyed.
- */
-class SimpleArena implements Arena {
-  protected heap: ArenaObject[];
-
-  constructor() {
-    this.heap = [];
-  }
-
-  put(obj: ArenaObject) {
-    this.heap.push(obj);
-  }
-
-  destroy() {
-    for (const obj of this.heap) {
-      obj.destroy();
-    }
-    this.heap = [];
-  }
-}
-
-
-/**
- * Arena that destroys all its objects once control has returned to the message
- * loop.
- */
-class SyncArena extends SimpleArena {
-  private isScheduled: boolean;
-
-  constructor() {
-    super();
-  }
-
-  pub(obj: MallocArenaObject) {
-    super.put(obj);
-    if (!this.isScheduled) {
-      this.schedule();
-    }
-    this.heap.push(obj);
-  }
-
-  private schedule() {
-    this.isScheduled = true;
-    Promise.resolve().then(() => {
-      this.isScheduled = false;
-      this.destroy();
-    });
-  }
-}
-
-export const arenaStack: Arena[] = [];
-arenaStack.push(new SyncArena());
-
-
-/**
- * Representation of monetary value in a given currency.
- */
-export class Amount extends MallocArenaObject {
-  constructor(emsc: EmscEnvironment, args?: AmountJson, arena?: Arena) {
-    super(emsc, arena);
-    if (args) {
-      this.nativePtr = emsc.allocFuncs.get_amount(args.value,
-                                            0,
-                                            args.fraction,
-                                            args.currency);
-    } else {
-      this.nativePtr = emsc.allocFuncs.get_amount(0, 0, 0, "");
-    }
-  }
-
-  static getZero(emsc: EmscEnvironment, currency: string, a?: Arena): Amount {
-    const am = new Amount(emsc, undefined, a);
-    const r = emsc.funcs.amount_get_zero(currency, am.nativePtr);
-    if (r !== GNUNET_OK) {
-      throw Error("invalid currency");
-    }
-    return am;
-  }
-
-
-  toNbo(a?: Arena): AmountNbo {
-    const x = new AmountNbo(this.emsc, a);
-    x.alloc();
-    this.emsc.funcs.amount_hton(x.nativePtr, this.nativePtr);
-    return x;
-  }
-
-  fromNbo(nbo: AmountNbo): void {
-    this.emsc.funcs.amount_ntoh(this.nativePtr, nbo.nativePtr);
-  }
-
-  get value() {
-    return this.emsc.funcs.get_value(this.nativePtr);
-  }
-
-  get fraction() {
-    return this.emsc.funcs.get_fraction(this.nativePtr);
-  }
-
-  get currency(): string {
-    return this.emsc.funcs.get_currency(this.nativePtr);
-  }
-
-  toJson(): AmountJson {
-    return {
-      currency: this.emsc.funcs.get_currency(this.nativePtr),
-      fraction: this.emsc.funcs.get_fraction(this.nativePtr),
-      value: this.emsc.funcs.get_value(this.nativePtr),
-    };
-  }
-
-  /**
-   * Add an amount to this amount.
-   */
-  add(a: Amount) {
-    const res = this.emsc.funcs.amount_add(this.nativePtr, a.nativePtr, this.nativePtr);
-    if (res < 1) {
-      // Overflow
-      return false;
-    }
-    return true;
-  }
-
-  /**
-   * Perform saturating subtraction on amounts.
-   */
-  sub(a: Amount) {
-    // this = this - a
-    const res = this.emsc.funcs.amount_subtract(this.nativePtr, this.nativePtr, a.nativePtr);
-    if (res === 0) {
-      // Underflow
-      return false;
-    }
-    if (res > 0) {
-      return true;
-    }
-    throw Error("Incompatible currencies");
-  }
-
-  cmp(a: Amount) {
-    // If we don't check this, the c code aborts.
-    if (this.currency !== a.currency) {
-      throw Error(`incomparable currencies (${this.currency} and ${a.currency})`);
-    }
-    return this.emsc.funcs.amount_cmp(this.nativePtr, a.nativePtr);
-  }
-
-  normalize() {
-    this.emsc.funcs.amount_normalize(this.nativePtr);
-  }
-}
-
-
-/**
- * Count the UTF-8 characters in a JavaScript string.
- */
-function countUtf8Bytes(str: string): number {
-  let s = str.length;
-  // JavaScript strings are UTF-16 arrays
-  for (let i = str.length - 1; i >= 0; i--) {
-    const code = str.charCodeAt(i);
-    if (code > 0x7f && code <= 0x7ff) {
-      // We need an extra byte in utf-8 here
-      s++;
-    } else if (code > 0x7ff && code <= 0xffff) {
-      // We need two extra bytes in utf-8 here
-      s += 2;
-    }
-    // Skip over the other surrogate
-    if (code >= 0xDC00 && code <= 0xDFFF) {
-      i--;
-    }
-  }
-  return s;
-}
-
-
-/**
- * Managed reference to a contiguous block of memory in the Emscripten heap.
- * Can be converted from / to a serialized representation.
- * Should contain only data, not pointers.
- */
-abstract class PackedArenaObject extends MallocArenaObject {
-  abstract size(): number;
-
-  constructor(emsc: EmscEnvironment, a?: Arena) {
-    super(emsc, a);
-  }
-
-  randomize(qual: RandomQuality = RandomQuality.STRONG): void {
-    this.emsc.funcs.random_block(qual, this.nativePtr, this.size());
-  }
-
-  toCrock(): string {
-    const d = this.emsc.allocFuncs.data_to_string_alloc(this.nativePtr, this.size());
-    const s = this.emsc.lib.UTF8ToString(d);
-    this.emsc.funcs.free(d);
-    return s;
-  }
-
-  toJson(): any {
-    // Per default, the json encoding of
-    // packed arena objects is just the crockford encoding.
-    // Subclasses typically want to override this.
-    return this.toCrock();
-  }
-
-  loadCrock(s: string) {
-    this.alloc();
-    // We need to get the javascript string
-    // to the emscripten heap first.
-    const buf = ByteArray.fromStringWithNull(this.emsc, s);
-    const res = this.emsc.funcs.string_to_data(buf.nativePtr,
-                                  s.length,
-                                  this.nativePtr,
-                                  this.size());
-    buf.destroy();
-    if (res < 1) {
-      throw {error: "wrong encoding"};
-    }
-  }
-
-  alloc() {
-    // FIXME: should the client be allowed to call alloc multiple times?
-    if (!this._nativePtr) {
-      this.nativePtr = this.emsc.allocFuncs.malloc(this.size());
-    }
-  }
-
-  hash(): HashCode {
-    const x = new HashCode(this.emsc);
-    x.alloc();
-    this.emsc.funcs.hash(this.nativePtr, this.size(), x.nativePtr);
-    return x;
-  }
-
-  hexdump() {
-    const bytes: string[] = [];
-    for (let i = 0; i < this.size(); i++) {
-      let b = this.emsc.lib.getValue(this.nativePtr + i, "i8");
-      b = (b + 256) % 256;
-      bytes.push("0".concat(b.toString(16)).slice(-2));
-    }
-    const lines: string[] = [];
-    for (let i = 0; i < bytes.length; i += 8) {
-      lines.push(bytes.slice(i, i + 8).join(","));
-    }
-    return lines.join("\n");
-  }
-}
-
-
-/**
- * Amount, encoded for network transmission.
- */
-export class AmountNbo extends PackedArenaObject {
-  size() {
-    return 24;
-  }
-
-  toJson(): any {
-    const a = new SimpleArena();
-    const am = new Amount(this.emsc, undefined, a);
-    am.fromNbo(this);
-    const json = am.toJson();
-    a.destroy();
-    return json;
-  }
-}
-
-
-/**
- * Create a packed arena object from the base32 crockford encoding.
- */
-function fromCrock<T extends PackedArenaObject>(emsc: EmscEnvironment, s: string, ctor: Ctor<T>): T {
-  const x: T = new ctor(emsc);
-  x.alloc();
-  x.loadCrock(s);
-  return x;
-}
-
-
-/**
- * Create a packed arena object from the base32 crockford encoding for objects
- * that have a special decoding function.
- */
-function fromCrockDecoded<T extends MallocArenaObject>(emsc: EmscEnvironment, s: string,
-                                                       ctor: Ctor<T>,
-                                                       decodeFn: (p: number, s: number) => number): T {
-  const obj = new ctor(emsc);
-  const buf = ByteArray.fromCrock(emsc, s);
-  obj.nativePtr = decodeFn(buf.nativePtr, buf.size());
-  buf.destroy();
-  return obj;
-}
-
-
-/**
- * Encode an object using a special encoding function.
- */
-function encode<T extends MallocArenaObject>(obj: T, encodeFn: any, arena?: Arena): ByteArray {
-  const ptr = obj.emsc.allocFuncs.malloc(PTR_SIZE);
-  const len = encodeFn(obj.nativePtr, ptr);
-  const res = new ByteArray(obj.emsc, len, undefined, arena);
-  res.nativePtr = obj.emsc.lib.getValue(ptr, "*");
-  obj.emsc.funcs.free(ptr);
-  return res;
-}
-
-
-/**
- * Private EdDSA key.
- */
-export class EddsaPrivateKey extends PackedArenaObject {
-  static create(emsc: EmscEnvironment, a?: Arena): EddsaPrivateKey {
-    const obj = new EddsaPrivateKey(emsc, a);
-    obj.nativePtr = emsc.allocFuncs.eddsa_key_create();
-    return obj;
-  }
-
-  size() {
-    return 32;
-  }
-
-  getPublicKey(a?: Arena): EddsaPublicKey {
-    const obj = new EddsaPublicKey(this.emsc, a);
-    obj.nativePtr = this.emsc.allocFuncs.eddsa_public_key_from_private(this.nativePtr);
-    return obj;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EddsaPrivateKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to an EdDSA private key.
- */
-export class EcdsaPrivateKey extends PackedArenaObject {
-  static create(emsc: EmscEnvironment, a?: Arena): EcdsaPrivateKey {
-    const obj = new EcdsaPrivateKey(emsc, a);
-    obj.nativePtr = emsc.allocFuncs.ecdsa_key_create();
-    return obj;
-  }
-
-  size() {
-    return 32;
-  }
-
-  getPublicKey(a?: Arena): EcdsaPublicKey {
-    const obj = new EcdsaPublicKey(this.emsc, a);
-    obj.nativePtr = this.emsc.allocFuncs.ecdsa_public_key_from_private(this.nativePtr);
-    return obj;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EcdsaPrivateKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to an ECDHE private key.
- */
-export class EcdhePrivateKey extends PackedArenaObject {
-  static create(emsc: EmscEnvironment, a?: Arena): EcdhePrivateKey {
-    const obj = new EcdhePrivateKey(emsc, a);
-    obj.nativePtr = emsc.allocFuncs.ecdhe_key_create();
-    return obj;
-  }
-
-  size() {
-    return 32;
-  }
-
-  getPublicKey(a?: Arena): EcdhePublicKey {
-    const obj = new EcdhePublicKey(this.emsc, a);
-    obj.nativePtr = this.emsc.allocFuncs.ecdhe_public_key_from_private(this.nativePtr);
-    return obj;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EcdhePrivateKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Constructor for a given type.
- */
-interface Ctor<T> {
-  new(emsc: EmscEnvironment): T;
-}
-
-
-/**
- * Low-level handle to an EdDSA public key.
- */
-export class EddsaPublicKey extends PackedArenaObject {
-  size() {
-    return 32;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EddsaPublicKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-/**
- * Low-level handle to an ECDSA public key.
- */
-export class EcdsaPublicKey extends PackedArenaObject {
-  size() {
-    return 32;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EcdsaPublicKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to an ECDHE public key.
- */
-export class EcdhePublicKey extends PackedArenaObject {
-  size() {
-    return 32;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): EcdhePublicKey {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to a blinding key secret.
- */
-export class RsaBlindingKeySecret extends PackedArenaObject {
-  size() {
-    return 32;
-  }
-
-  /**
-   * Create a random blinding key secret.
-   */
-  static create(emsc: EmscEnvironment, a?: Arena): RsaBlindingKeySecret {
-    const o = new RsaBlindingKeySecret(emsc, a);
-    o.alloc();
-    o.randomize();
-    return o;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): RsaBlindingKeySecret {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to a hash code.
- */
-export class HashCode extends PackedArenaObject {
-  size() {
-    return 64;
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string): HashCode {
-    return fromCrock(emsc, s, this);
-  }
-
-  random(qual: RandomQuality = RandomQuality.STRONG) {
-    this.alloc();
-    this.emsc.funcs.hash_create_random(qual, this.nativePtr);
-  }
-}
-
-
-/**
- * Low-level handle to a byte array.
- */
-export class ByteArray extends PackedArenaObject {
-  private allocatedSize: number;
-
-  size() {
-    return this.allocatedSize;
-  }
-
-  constructor(public emsc: EmscEnvironment, desiredSize: number, init?: number, a?: Arena) {
-    super(emsc, a);
-    if (init === undefined) {
-      this.nativePtr = this.emsc.allocFuncs.malloc(desiredSize);
-    } else {
-      this.nativePtr = init;
-    }
-    this.allocatedSize = desiredSize;
-  }
-
-  static fromStringWithoutNull(emsc: EmscEnvironment, s: string, a?: Arena): ByteArray {
-    // UTF-8 bytes, including 0-terminator
-    const terminatedByteLength = countUtf8Bytes(s) + 1;
-    const hstr = emsc.allocFuncs.malloc(terminatedByteLength);
-    emsc.lib.stringToUTF8(s, hstr, terminatedByteLength);
-    return new ByteArray(emsc, terminatedByteLength - 1, hstr, a);
-  }
-
-  static fromStringWithNull(emsc: EmscEnvironment, s: string, a?: Arena): ByteArray {
-    // UTF-8 bytes, including 0-terminator
-    const terminatedByteLength = countUtf8Bytes(s) + 1;
-    const hstr = emsc.allocFuncs.malloc(terminatedByteLength);
-    emsc.lib.stringToUTF8(s, hstr, terminatedByteLength);
-    return new ByteArray(emsc, terminatedByteLength, hstr, a);
-  }
-
-  static fromCrock(emsc: EmscEnvironment, s: string, a?: Arena): ByteArray {
-    // this one is a bit more complicated than the other fromCrock functions,
-    // since we don't have a fixed size
-    const byteLength = countUtf8Bytes(s);
-    const hstr = emsc.allocFuncs.malloc(byteLength + 1);
-    emsc.lib.stringToUTF8(s, hstr, byteLength + 1);
-    const decodedLen = Math.floor((byteLength * 5) / 8);
-    const ba = new ByteArray(emsc, decodedLen, undefined, a);
-    const res = emsc.funcs.string_to_data(hstr, byteLength, ba.nativePtr, decodedLen);
-    emsc.funcs.free(hstr);
-    if (res !== GNUNET_OK) {
-      throw Error("decoding failed");
-    }
-    return ba;
-  }
-}
-
-
-/**
- * Data to sign, together with a header that includes a purpose id
- * and size.
- */
-export class EccSignaturePurpose extends PackedArenaObject {
-  size() {
-    return this.payloadSize + 8;
-  }
-
-  private payloadSize: number;
-
-  constructor(emsc: EmscEnvironment,
-              purpose: SignaturePurpose,
-              payload: PackedArenaObject,
-              a?: Arena) {
-    super(emsc, a);
-    this.nativePtr = emsc.allocFuncs.purpose_create(purpose,
-                                                      payload.nativePtr,
-                                                      payload.size());
-    this.payloadSize = payload.size();
-  }
-}
-
-
-abstract class SignatureStruct {
-  abstract fieldTypes(): any[];
-
-  abstract purpose(): SignaturePurpose;
-
-  private members: any = {};
-
-  constructor(public emsc: EmscEnvironment, x: { [name: string]: any }) {
-    for (const k in x) {
-      this.set(k, x[k]);
-    }
-  }
-
-  toPurpose(a?: Arena): EccSignaturePurpose {
-    let totalSize = 0;
-    for (const f of this.fieldTypes()) {
-      const name = f[0];
-      const member = this.members[name];
-      if (!member) {
-        throw Error(`Member ${name} not set`);
-      }
-      totalSize += member.size();
-    }
-
-    const buf = this.emsc.allocFuncs.malloc(totalSize);
-    let ptr = buf;
-    for (const f of this.fieldTypes()) {
-      const name = f[0];
-      const member = this.members[name];
-      const size = member.size();
-      this.emsc.funcs.memmove(ptr, member.nativePtr, size);
-      ptr += size;
-    }
-    const ba = new ByteArray(this.emsc, totalSize, buf, a);
-    return new EccSignaturePurpose(this.emsc, this.purpose(), ba);
-  }
-
-
-  toJson() {
-    const res: any = {};
-    for (const f of this.fieldTypes()) {
-      const name = f[0];
-      const member = this.members[name];
-      if (!member) {
-        throw Error(`Member ${name} not set`);
-      }
-      res[name] = member.toJson();
-    }
-    res.purpose = this.purpose();
-    return res;
-  }
-
-  protected set(name: string, value: PackedArenaObject) {
-    const typemap: any = {};
-    for (const f of this.fieldTypes()) {
-      typemap[f[0]] = f[1];
-    }
-    if (!(name in typemap)) {
-      throw Error(`Key ${name} not found`);
-    }
-    if (!(value instanceof typemap[name])) {
-      throw Error(`Wrong type for ${name}`);
-    }
-    this.members[name] = value;
-  }
-}
-
-
-/**
- * Arguments to constructor of [[WithdrawRequestPS]].
- */
-export interface WithdrawRequestPS_Args {
-  /**
-   * Reserve public key.
-   */
-  reserve_pub: EddsaPublicKey;
-  /**
-   * Amount with fee.
-   */
-  amount_with_fee: AmountNbo;
-  /**
-   * Withdraw fee.
-   */
-  withdraw_fee: AmountNbo;
-  /**
-   * Hash of denomination public key.
-   */
-  h_denomination_pub: HashCode;
-  /**
-   * Hash of coin envelope.
-   */
-  h_coin_envelope: HashCode;
-}
-
-
-/**
- * Low-level handle to a WithdrawRequest signature structure.
- */
-export class WithdrawRequestPS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: WithdrawRequestPS_Args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.RESERVE_WITHDRAW;
-  }
-
-  fieldTypes() {
-    return [
-      ["reserve_pub", EddsaPublicKey],
-      ["amount_with_fee", AmountNbo],
-      ["withdraw_fee", AmountNbo],
-      ["h_denomination_pub", HashCode],
-      ["h_coin_envelope", HashCode],
-    ];
-  }
-}
-
-
-/**
- * Arguments for constructor or [[PaybackRequestPS]].
- */
-export interface PaybackRequestPS_args {
-  coin_pub: EddsaPublicKey;
-  h_denom_pub: HashCode;
-  coin_blind: RsaBlindingKeySecret;
-}
-
-
-/**
- * Low-level handle to a PaybackRequest signature structure.
- */
-export class PaybackRequestPS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: PaybackRequestPS_args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.WALLET_COIN_PAYBACK;
-  }
-
-  fieldTypes() {
-    return [
-      ["coin_pub", EddsaPublicKey],
-      ["h_denom_pub", HashCode],
-      ["coin_blind", RsaBlindingKeySecret],
-    ];
-  }
-}
-
-
-/**
- * Arguments for constructor of [[RefreshMeltCoinAffirmationPS]].
- */
-interface RefreshMeltCoinAffirmationPS_Args {
-  session_hash: HashCode;
-  amount_with_fee: AmountNbo;
-  melt_fee: AmountNbo;
-  coin_pub: EddsaPublicKey;
-}
-
-/**
- * Low-level handle to a RefreshMeltCoinAffirmationPS signature structure.
- */
-export class RefreshMeltCoinAffirmationPS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: RefreshMeltCoinAffirmationPS_Args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.WALLET_COIN_MELT;
-  }
-
-  fieldTypes() {
-    return [
-      ["session_hash", HashCode],
-      ["amount_with_fee", AmountNbo],
-      ["melt_fee", AmountNbo],
-      ["coin_pub", EddsaPublicKey],
-    ];
-  }
-}
-
-
-/**
- * Arguments for constructor of [[MasterWireFeePS]].
- */
-interface MasterWireFeePS_Args {
-  /**
-   * Hash of wire method.
-   */
-  h_wire_method: HashCode;
-  /**
-   * Start date.
-   */
-  start_date: AbsoluteTimeNbo;
-  /**
-   * End date.
-   */
-  end_date: AbsoluteTimeNbo;
-  /**
-   * Wire fee.
-   */
-  wire_fee: AmountNbo;
-  /**
-   * Closing fee.
-   */
-  closing_fee: AmountNbo;
-}
-
-
-/**
- * Low-level handle to a structure being signed over.
- */
-export class MasterWireFeePS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: MasterWireFeePS_Args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.MASTER_WIRE_FEES;
-  }
-
-  fieldTypes() {
-    return [
-      ["h_wire_method", HashCode],
-      ["start_date", AbsoluteTimeNbo],
-      ["end_date", AbsoluteTimeNbo],
-      ["wire_fee", AmountNbo],
-      ["closing_fee", AmountNbo],
-    ];
-  }
-}
-
-
-/**
- * Low-level handle to an absolute time in network byte order (NBO).
- */
-export class AbsoluteTimeNbo extends PackedArenaObject {
-  static fromTalerString(emsc: EmscEnvironment, s: string): AbsoluteTimeNbo {
-    const x = new AbsoluteTimeNbo(emsc);
-    x.alloc();
-    const r = /Date\(([0-9]+)\)/;
-    const m = r.exec(s);
-    if (!m || m.length !== 2) {
-      throw Error();
-    }
-    const n = parseInt(m[1], 10) * 1000000;
-    // XXX: This only works up to 54 bit numbers.
-    set64(emsc, x.nativePtr, n);
-    return x;
-  }
-
-  static fromStampSeconds(emsc: EmscEnvironment, stamp: number): AbsoluteTimeNbo {
-    const x = new AbsoluteTimeNbo(emsc);
-    x.alloc();
-    // XXX: This only works up to 54 bit numbers.
-    set64(emsc, x.nativePtr, stamp * 1000000);
-    return x;
-  }
-
-
-  size() {
-    return 8;
-  }
-}
-
-
-// XXX: This only works up to 54 bit numbers.
-function set64(emsc: EmscEnvironment, p: number, n: number) {
-  for (let i = 0; i < 8; ++i) {
-    emsc.lib.setValue(p + (7 - i), n & 0xFF, "i8");
-    n = Math.floor(n / 256);
-  }
-}
-
-// XXX: This only works up to 54 bit numbers.
-function set32(emsc: EmscEnvironment, p: number, n: number) {
-  for (let i = 0; i < 4; ++i) {
-    emsc.lib.setValue(p + (3 - i), n & 0xFF, "i8");
-    n = Math.floor(n / 256);
-  }
-}
-
-
-/**
- * Low-level handle to an unsigned 64-bit value.
- */
-export class UInt64 extends PackedArenaObject {
-  static fromNumber(emsc: EmscEnvironment, n: number): UInt64 {
-    const x = new UInt64(emsc);
-    x.alloc();
-    set64(emsc, x.nativePtr, n);
-    return x;
-  }
-
-  size() {
-    return 8;
-  }
-}
-
-
-/**
- * Low-level handle to an unsigned 32-bit value.
- */
-export class UInt32 extends PackedArenaObject {
-  static fromNumber(emsc: EmscEnvironment, n: number): UInt32 {
-    const x = new UInt32(emsc);
-    x.alloc();
-    set32(emsc, x.nativePtr, n);
-    return x;
-  }
-
-  size() {
-    return 4;
-  }
-}
-
-
-/**
- * Argument to the constructor of [[DepositRequestPS]].
- */
-export interface DepositRequestPS_Args {
-  /**
-   * Contract hash.
-   */
-  h_contract: HashCode;
-  /**
-   * Wire info hash.
-   */
-  h_wire: HashCode;
-  /**
-   * Timestamp.
-   */
-  timestamp: AbsoluteTimeNbo;
-  /**
-   * Refund deadline.
-   */
-  refund_deadline: AbsoluteTimeNbo;
-  /**
-   * Amount with fee.
-   */
-  amount_with_fee: AmountNbo;
-  /**
-   * Deposit fee.
-   */
-  deposit_fee: AmountNbo;
-  /**
-   * Merchant public key.
-   */
-  merchant: EddsaPublicKey;
-  /**
-   * Public key of the coin being deposited.
-   */
-  coin_pub: EddsaPublicKey;
-}
-
-
-/**
- * Low-level handle to a struct being signed over.
- */
-export class DepositRequestPS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: DepositRequestPS_Args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.WALLET_COIN_DEPOSIT;
-  }
-
-  fieldTypes() {
-    return [
-      ["h_contract", HashCode],
-      ["h_wire", HashCode],
-      ["timestamp", AbsoluteTimeNbo],
-      ["refund_deadline", AbsoluteTimeNbo],
-      ["amount_with_fee", AmountNbo],
-      ["deposit_fee", AmountNbo],
-      ["merchant", EddsaPublicKey],
-      ["coin_pub", EddsaPublicKey],
-    ];
-  }
-}
-
-
-interface CoinLinkSignaturePS_args {
-  h_denom_pub: HashCode;
-  old_coin_pub: EddsaPublicKey;
-  transfer_pub: EcdhePublicKey;
-  coin_envelope_hash: HashCode;
-}
-
-
-export class CoinLinkSignaturePS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: CoinLinkSignaturePS_args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.WALLET_COIN_LINK;
-  }
-
-  fieldTypes() {
-    return [
-      ["h_denom_pub", HashCode],
-      ["old_coin_pub", EddsaPublicKey],
-      ["transfer_pub", EcdhePublicKey],
-      ["coin_envelope_hash", HashCode],
-    ];
-  }
-}
-
-
-/**
- * Arguments for constuctor of [[DenominationKeyValidityPS]].
- */
-export interface DenominationKeyValidityPS_args {
-  master: EddsaPublicKey;
-  start: AbsoluteTimeNbo;
-  expire_withdraw: AbsoluteTimeNbo;
-  expire_spend: AbsoluteTimeNbo;
-  expire_legal: AbsoluteTimeNbo;
-  value: AmountNbo;
-  fee_withdraw: AmountNbo;
-  fee_deposit: AmountNbo;
-  fee_refresh: AmountNbo;
-  fee_refund: AmountNbo;
-  denom_hash: HashCode;
-}
-
-
-/**
- * Low-level handle to a structure being signed over.
- */
-export class DenominationKeyValidityPS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: DenominationKeyValidityPS_args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.MASTER_DENOMINATION_KEY_VALIDITY;
-  }
-
-  fieldTypes() {
-    return [
-      ["master", EddsaPublicKey],
-      ["start", AbsoluteTimeNbo],
-      ["expire_withdraw", AbsoluteTimeNbo],
-      ["expire_spend", AbsoluteTimeNbo],
-      ["expire_legal", AbsoluteTimeNbo],
-      ["value", AmountNbo],
-      ["fee_withdraw", AmountNbo],
-      ["fee_deposit", AmountNbo],
-      ["fee_refresh", AmountNbo],
-      ["fee_refund", AmountNbo],
-      ["denom_hash", HashCode],
-    ];
-  }
-}
-
-/**
- * Arguments to constructor of [[PaymentSignaturePS]].
- */
-export interface PaymentSignaturePS_args {
-  /**
-   * Contract hash.
-   */
-  contract_hash: HashCode;
-}
-
-
-/**
- * Low-level handle to a structure being signed over.
- */
-export class PaymentSignaturePS extends SignatureStruct {
-  constructor(emsc: EmscEnvironment, w: PaymentSignaturePS_args) {
-    super(emsc, w);
-  }
-
-  purpose() {
-    return SignaturePurpose.MERCHANT_PAYMENT_OK;
-  }
-
-  fieldTypes() {
-    return [
-      ["contract_hash", HashCode],
-    ];
-  }
-}
-
-
-/**
- * Low-level handle to an RsaPrivateKey.
- */
-export class RsaPrivateKey extends MallocArenaObject {
-  static fromCrock(emsc: EmscEnvironment, s: string): RsaPrivateKey {
-    return fromCrockDecoded(emsc, s, this, emsc.allocFuncs.rsa_private_key_decode);
-  }
-
-  static create(emsc: EmscEnvironment, bitLen: number, a?: Arena): RsaPrivateKey {
-    const obj = new RsaPrivateKey(emsc, a);
-    obj.nativePtr = emsc.allocFuncs.rsa_private_key_create(bitLen);
-    return obj;
-  }
-
-  toCrock() {
-    return this.encode().toCrock();
-  }
-
-
-  getPublicKey(a?: Arena): RsaPublicKey {
-    const obj = new RsaPublicKey(this.emsc, a);
-    obj.nativePtr = this.emsc.allocFuncs.rsa_private_key_get_public(this.nativePtr);
-    return obj;
-  }
-
-  destroy() {
-    this.emsc.funcs.rsa_public_key_free(this.nativePtr);
-    this.nativePtr = 0;
-  }
-
-  encode(arena?: Arena): ByteArray {
-    return encode(this, this.emsc.allocFuncs.rsa_private_key_encode);
-  }
-}
-
-
-/**
- * Low-level handle to an RsaPublicKey.
- */
-export class RsaPublicKey extends MallocArenaObject {
-  static fromCrock(emsc: EmscEnvironment, s: string): RsaPublicKey {
-    return fromCrockDecoded(emsc, s, this, emsc.allocFuncs.rsa_public_key_decode);
-  }
-
-  toCrock() {
-    return this.encode().toCrock();
-  }
-
-  destroy() {
-    this.emsc.funcs.rsa_public_key_free(this.nativePtr);
-    this.nativePtr = 0;
-  }
-
-  encode(arena?: Arena): ByteArray {
-    return encode(this, this.emsc.allocFuncs.rsa_public_key_encode);
-  }
-}
-
-
-/**
- * Low-level handle to an EddsaSignature.
- */
-export class EddsaSignature extends PackedArenaObject {
-  size() {
-    return 64;
-  }
-  static fromCrock(emsc: EmscEnvironment, s: string): EddsaSignature {
-    return fromCrock(emsc, s, this);
-  }
-}
-
-
-/**
- * Low-level handle to an RsaSignature.
- */
-export class RsaSignature extends MallocArenaObject {
-  static fromCrock(emsc: EmscEnvironment, s: string, a?: Arena) {
-    return fromCrockDecoded(emsc, s, this, emsc.allocFuncs.rsa_signature_decode);
-  }
-
-  encode(arena?: Arena): ByteArray {
-    return encode(this, this.emsc.allocFuncs.rsa_signature_encode);
-  }
-
-  destroy() {
-    this.emsc.funcs.rsa_signature_free(this.nativePtr);
-    this.nativePtr = 0;
-  }
-}
-
-
-/**
- * Blind a value so it can be blindly signed.
- */
-export function rsaBlind(hashCode: HashCode,
-                         blindingKey: RsaBlindingKeySecret,
-                         pkey: RsaPublicKey,
-                         arena?: Arena): ByteArray|null {
-  const emsc: EmscEnvironment = hashCode.emsc;
-  const buf_ptr_out = emsc.allocFuncs.malloc(PTR_SIZE);
-  const buf_size_out = emsc.allocFuncs.malloc(PTR_SIZE);
-  const res = emsc.allocFuncs.rsa_blind(hashCode.nativePtr,
-                                          blindingKey.nativePtr,
-                                          pkey.nativePtr,
-                                          buf_ptr_out,
-                                          buf_size_out);
-  const buf_ptr = emsc.lib.getValue(buf_ptr_out, "*");
-  const buf_size = emsc.lib.getValue(buf_size_out, "*");
-  emsc.funcs.free(buf_ptr_out);
-  emsc.funcs.free(buf_size_out);
-  if (res !== GNUNET_OK) {
-    // malicious key
-    return null;
-  }
-  return new ByteArray(emsc, buf_size, buf_ptr, arena);
-}
-
-
-/**
- * Sign data using EdDSA.
- */
-export function eddsaSign(purpose: EccSignaturePurpose,
-                          priv: EddsaPrivateKey,
-                          a?: Arena): EddsaSignature {
-  const sig = new EddsaSignature(purpose.emsc, a);
-  sig.alloc();
-  const res = purpose.emsc.funcs.eddsa_sign(priv.nativePtr, purpose.nativePtr, sig.nativePtr);
-  if (res < 1) {
-    throw Error("EdDSA signing failed");
-  }
-  return sig;
-}
-
-
-/**
- * Verify EdDSA-signed data.
- */
-export function eddsaVerify(purposeNum: number,
-                            verify: EccSignaturePurpose,
-                            sig: EddsaSignature,
-                            pub: EddsaPublicKey,
-                            a?: Arena): boolean {
-  const r = verify.emsc.funcs.eddsa_verify(purposeNum,
-                                      verify.nativePtr,
-                                      sig.nativePtr,
-                                      pub.nativePtr);
-  return r === GNUNET_OK;
-}
-
-
-export function rsaVerify(h: HashCode,
-                          sig: RsaSignature,
-                          pub: RsaPublicKey) {
-  const r = h.emsc.funcs.rsa_verify(h.nativePtr,
-                                    sig.nativePtr,
-                                    pub.nativePtr);
-  return r === GNUNET_OK;
-}
-
-
-/**
- * Unblind a blindly signed value.
- */
-export function rsaUnblind(sig: RsaSignature,
-                           bk: RsaBlindingKeySecret,
-                           pk: RsaPublicKey,
-                           a?: Arena): RsaSignature {
-  const x = new RsaSignature(sig.emsc, a);
-  x.nativePtr = sig.emsc.allocFuncs.rsa_unblind(sig.nativePtr,
-                                              bk.nativePtr,
-                                              pk.nativePtr);
-  return x;
-}
-
-
-type TransferSecretP = HashCode;
-
-/**
- * A fresh coin generated from a sed.
- */
-export interface FreshCoin {
-  /**
-   * The coin's private key.
-   */
-  priv: EddsaPrivateKey;
-  /**
-   * The blinding key to use for withdrawal.
-   */
-  blindingKey: RsaBlindingKeySecret;
-}
-
-/**
- * Diffie-Hellman operation between an ECDHE private key
- * and an EdDSA public key.
- */
-export function ecdhEddsa(priv: EcdhePrivateKey,
-                          pub: EddsaPublicKey): HashCode {
-  const h = new HashCode(priv.emsc);
-  h.alloc();
-  const res = priv.emsc.funcs.ecdh_eddsa(priv.nativePtr, pub.nativePtr, h.nativePtr);
-  if (res !== GNUNET_OK) {
-    throw Error("ecdh_eddsa failed");
-  }
-  return h;
-}
-
-export function rsaSignBlinded(priv: RsaPrivateKey,
-                               msg: ByteArray): RsaSignature {
-  const sig = new RsaSignature(priv.emsc);
-  sig.nativePtr = priv.emsc.allocFuncs.rsa_sign_blinded (priv.nativePtr,
-                                                      msg.nativePtr,
-                                                      msg.size());
-  return sig;
-}
-
-
-
-/**
- * Derive a fresh coin from the given seed.  Used during refreshing.
- */
-export function setupFreshCoin(secretSeed: TransferSecretP,
-                               coinIndex: number): FreshCoin {
-  const emsc: EmscEnvironment = secretSeed.emsc; 
-  const priv = new EddsaPrivateKey(emsc);
-  priv.isWeak = true;
-  const blindingKey = new RsaBlindingKeySecret(emsc);
-  blindingKey.isWeak = true;
-  const buf = new ByteArray(emsc, priv.size() + blindingKey.size());
-
-  emsc.funcs.setup_fresh_coin(secretSeed.nativePtr, coinIndex, buf.nativePtr);
-
-  priv.nativePtr = buf.nativePtr;
-  blindingKey.nativePtr = buf.nativePtr + priv.size();
-
-  return { priv, blindingKey };
-}
diff --git a/src/crypto/nodeEmscriptenLoader.ts b/src/crypto/nodeEmscriptenLoader.ts
deleted file mode 100644
index 65d54a702..000000000
--- a/src/crypto/nodeEmscriptenLoader.ts
+++ /dev/null
@@ -1,101 +0,0 @@
-
-import { EmscEnvironment } from "./emscInterface";
-import { CryptoImplementation } from "./cryptoImplementation";
-
-import fs = require("fs");
-
-export class NodeEmscriptenLoader {
-  private cachedEmscEnvironment: EmscEnvironment | undefined = undefined;
-  private cachedEmscEnvironmentPromise:
-    | Promise<EmscEnvironment>
-    | undefined = undefined;
-
-    private async getWasmBinary(): Promise<Uint8Array> {
-      // @ts-ignore
-      const akonoGetData = global.__akono_getData;
-      if (akonoGetData) {
-        // We're running embedded node on Android
-        console.log("reading wasm binary from akono");
-        const data = akonoGetData("taler-emscripten-lib.wasm");
-        // The data we get is base64-encoded binary data
-        let buf = new Buffer(data, 'base64');
-        return new Uint8Array(buf);
-  
-      } else {
-        // We're in a normal node environment
-        const binaryPath = __dirname + "/../../../emscripten/taler-emscripten-lib.wasm";
-        const wasmBinary = new Uint8Array(fs.readFileSync(binaryPath));
-        return wasmBinary;
-      }
-    }
-  
-    async getEmscriptenEnvironment(): Promise<EmscEnvironment> {
-      if (this.cachedEmscEnvironment) {
-        return this.cachedEmscEnvironment;
-      }
-  
-      if (this.cachedEmscEnvironmentPromise) {
-        return this.cachedEmscEnvironmentPromise;
-      }
-  
-      let lib: any;
-  
-      const wasmBinary = await this.getWasmBinary();
-  
-      return new Promise((resolve, reject) => {
-        // Arguments passed to the emscripten prelude
-        const libArgs = {
-          wasmBinary,
-          onRuntimeInitialized: () => {
-            if (!lib) {
-              console.error("fatal emscripten initialization error");
-              return;
-            }
-            this.cachedEmscEnvironmentPromise = undefined;
-            this.cachedEmscEnvironment = new EmscEnvironment(lib);
-            resolve(this.cachedEmscEnvironment);
-          },
-        };
-  
-        // Make sure that TypeScript doesn't try
-        // to check the taler-emscripten-lib.
-        const indirectRequire = require;
-  
-        const g = global;
-  
-        // unavoidable hack, so that emscripten detects
-        // the environment as node even though importScripts
-        // is present.
-  
-        // @ts-ignore
-        const savedImportScripts = g.importScripts;
-        // @ts-ignore
-        delete g.importScripts;
-        // @ts-ignore
-        const savedCrypto = g.crypto;
-        // @ts-ignore
-        delete g.crypto;
-  
-        // Assume that the code is run from the dist/ directory.
-        const libFn = indirectRequire(
-          "../../../emscripten/taler-emscripten-lib.js",
-        );
-        lib = libFn(libArgs);
-  
-        // @ts-ignore
-        g.importScripts = savedImportScripts;
-        // @ts-ignore
-        g.crypto = savedCrypto;
-  
-        if (!lib) {
-          throw Error("could not load taler-emscripten-lib.js");
-        }
-  
-        if (!lib.ccall) {
-          throw Error(
-            "sanity check failed: taler-emscripten lib does not have 'ccall'",
-          );
-        }
-      });
-    }
-}
diff --git a/src/crypto/nodeProcessWorker.ts b/src/crypto/nodeProcessWorker.ts
index c5d0f2e71..8ff149788 100644
--- a/src/crypto/nodeProcessWorker.ts
+++ b/src/crypto/nodeProcessWorker.ts
@@ -84,7 +84,6 @@ export class Worker {
     });
 
     this.child.on("message", (msg: any) => {
-      console.log("nodeProcessWorker got child message", msg);
       this.dispatchMessage(msg);
     });
   }
@@ -114,7 +113,6 @@ export class Worker {
    * Forcibly terminate the worker thread.
    */
   terminate () {
-    console.log("terminating node.js worker");
     this.child.kill("SIGINT");
   }
 }
diff --git a/src/crypto/nodeWorkerEntry.ts b/src/crypto/nodeWorkerEntry.ts
index 1ed16f870..1e088d987 100644
--- a/src/crypto/nodeWorkerEntry.ts
+++ b/src/crypto/nodeWorkerEntry.ts
@@ -14,20 +14,13 @@
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
-
 // tslint:disable:no-var-requires
 
-import fs = require("fs");
-import vm = require("vm");
-import { NodeEmscriptenLoader } from "./nodeEmscriptenLoader";
 import { CryptoImplementation } from "./cryptoImplementation";
 
-const loader = new NodeEmscriptenLoader();
-
 async function handleRequest(operation: string, id: number, args: string[]) {
-  let emsc = await loader.getEmscriptenEnvironment();
 
-  const impl = new CryptoImplementation(emsc);
+  const impl = new CryptoImplementation();
 
   if (!(operation in impl)) {
     console.error(`crypto operation '${operation}' not found`);
@@ -42,16 +35,12 @@ async function handleRequest(operation: string, id: number, args: string[]) {
       console.error("process.send not available");
     }
   } catch (e) {
-    console.log("error during operation", e);
+    console.error("error during operation", e);
     return;
   }
 }
 
 process.on("message", (msgStr: any) => {
-  console.log("got message in node worker entry", msgStr);
-
-  console.log("typeof msg", typeof msgStr);
-
   const msg = JSON.parse(msgStr);
 
   const args = msg.data.args;
@@ -76,5 +65,5 @@ process.on("message", (msgStr: any) => {
 });
 
 process.on("uncaughtException", (err: any) => {
-  console.log("uncaught exception in node worker entry", err);
+  console.error("uncaught exception in node worker entry", err);
 });
diff --git a/src/crypto/kdf.ts b/src/crypto/primitives/kdf.ts
index 082963074..082963074 100644
--- a/src/crypto/kdf.ts
+++ b/src/crypto/primitives/kdf.ts
diff --git a/src/crypto/nacl-fast.ts b/src/crypto/primitives/nacl-fast.ts
index 418662e8d..66ab78162 100644
--- a/src/crypto/nacl-fast.ts
+++ b/src/crypto/primitives/nacl-fast.ts
@@ -2342,7 +2342,6 @@ function crypto_hash(out: Uint8Array, m: Uint8Array, n: number) {
   const hh = new Int32Array(8);
   const hl = new Int32Array(8);
   const x = new Uint8Array(256);
-  let i;
   let b = n;
 
   hh[0] = 0x6a09e667;
@@ -2366,7 +2365,7 @@ function crypto_hash(out: Uint8Array, m: Uint8Array, n: number) {
   crypto_hashblocks_hl(hh, hl, m, n);
   n %= 128;
 
-  for (i = 0; i < n; i++) x[i] = m[b - n + i];
+  for (let i = 0; i < n; i++) x[i] = m[b - n + i];
   x[n] = 128;
 
   n = 256 - 128 * (n < 112 ? 1 : 0);
@@ -2374,11 +2373,86 @@ function crypto_hash(out: Uint8Array, m: Uint8Array, n: number) {
   ts64(x, n - 8, (b / 0x20000000) | 0, b << 3);
   crypto_hashblocks_hl(hh, hl, x, n);
 
-  for (i = 0; i < 8; i++) ts64(out, 8 * i, hh[i], hl[i]);
+  for (let i = 0; i < 8; i++)
+    ts64(out, 8 * i, hh[i], hl[i]);
 
   return 0;
 }
 
+
+/**
+ * Incremental version of crypto_hash.
+ */
+export class HashState {
+  private hh = new Int32Array(8);
+  private hl = new Int32Array(8);
+
+  private next = new Uint8Array(128);
+  private p = 0;
+  private total = 0;
+
+  constructor() {
+    this.hh[0] = 0x6a09e667;
+    this.hh[1] = 0xbb67ae85;
+    this.hh[2] = 0x3c6ef372;
+    this.hh[3] = 0xa54ff53a;
+    this.hh[4] = 0x510e527f;
+    this.hh[5] = 0x9b05688c;
+    this.hh[6] = 0x1f83d9ab;
+    this.hh[7] = 0x5be0cd19;
+  
+    this.hl[0] = 0xf3bcc908;
+    this.hl[1] = 0x84caa73b;
+    this.hl[2] = 0xfe94f82b;
+    this.hl[3] = 0x5f1d36f1;
+    this.hl[4] = 0xade682d1;
+    this.hl[5] = 0x2b3e6c1f;
+    this.hl[6] = 0xfb41bd6b;
+    this.hl[7] = 0x137e2179;
+  }
+
+  update(data: Uint8Array): HashState {
+    this.total += data.length;
+    let i = 0;
+    while (i < data.length) {
+      const r = 128 - this.p;
+      if (r > (data.length - i)) {
+        for (let j = 0; i + j < data.length; j++) {
+          this.next[this.p + j] = data[i + j];
+        }
+        this.p += data.length - i;
+        break;
+      } else {
+        for (let j = 0; this.p + j < 128; j++) {
+          this.next[this.p + j] = data[i + j];
+        }
+        crypto_hashblocks_hl(this.hh, this.hl, this.next, 128);
+        i += 128 - this.p;
+        this.p = 0;
+      }
+    }
+    return this;
+  }
+
+  finish(): Uint8Array {
+    const out = new Uint8Array(64);
+    let n = this.p;
+    const x = new Uint8Array(256);
+    let b = this.total;
+    for (let i = 0; i < n; i++) x[i] = this.next[i];
+    x[n] = 128;
+  
+    n = 256 - 128 * (n < 112 ? 1 : 0);
+    x[n - 9] = 0;
+    ts64(x, n - 8, (b / 0x20000000) | 0, b << 3);
+    crypto_hashblocks_hl(this.hh, this.hl, x, n);
+  
+    for (let i = 0; i < 8; i++)
+      ts64(out, 8 * i, this.hh[i], this.hl[i]);
+    return out;
+  }
+}
+
 function add(p: Float64Array[], q: Float64Array[]) {
   var a = gf(),
     b = gf(),
diff --git a/src/crypto/sha256.ts b/src/crypto/primitives/sha256.ts
index f4f6690c7..f4f6690c7 100644
--- a/src/crypto/sha256.ts
+++ b/src/crypto/primitives/sha256.ts
diff --git a/src/crypto/synchronousWorker.ts b/src/crypto/synchronousWorker.ts
index 41ebee4f3..12eecde9a 100644
--- a/src/crypto/synchronousWorker.ts
+++ b/src/crypto/synchronousWorker.ts
@@ -16,9 +16,6 @@
 
 import { CryptoImplementation } from "./cryptoImplementation";
 
-import { NodeEmscriptenLoader } from "./nodeEmscriptenLoader";
-
-import fs = require("fs");
 import { CryptoWorkerFactory } from "./cryptoApi";
 import { CryptoWorker } from "./cryptoWorker";
 
@@ -56,8 +53,6 @@ export class SynchronousCryptoWorker {
    */
   onerror: undefined | ((m: any) => void);
 
-  private emscriptenLoader = new NodeEmscriptenLoader();
-
   constructor() {
     this.onerror = undefined;
     this.onmessage = undefined;
@@ -84,9 +79,7 @@ export class SynchronousCryptoWorker {
   }
 
   private async handleRequest(operation: string, id: number, args: string[]) {
-    let emsc = await this.emscriptenLoader.getEmscriptenEnvironment();
-
-    const impl = new CryptoImplementation(emsc);
+    const impl = new CryptoImplementation();
 
     if (!(operation in impl)) {
       console.error(`crypto operation '${operation}' not found`);
diff --git a/src/crypto/talerCrypto-test.ts b/src/crypto/talerCrypto-test.ts
index 3f9d6f398..59949dbd3 100644
--- a/src/crypto/talerCrypto-test.ts
+++ b/src/crypto/talerCrypto-test.ts
@@ -29,8 +29,8 @@ import {
   rsaUnblind,
   rsaVerify,
 } from "./talerCrypto";
-import { hmacSha512, sha512, kdf } from "./kdf";
-import nacl = require("./nacl-fast");
+import { sha512, kdf } from "./primitives/kdf";
+import nacl = require("./primitives/nacl-fast");
 
 function hexToBytes(hex: string) {
   for (var bytes = [], c = 0; c < hex.length; c += 2)
@@ -159,3 +159,43 @@ test("taler-exchange-tvg blind signing", t => {
   const v = rsaVerify(decodeCrock(messageHash), decodeCrock(sig), decodeCrock(rsaPublicKey));
   t.true(v);
 });
+
+
+test("incremental hashing #1", (t) => {
+  const n = 1024;
+  const d = nacl.randomBytes(n);
+
+  const h1 = nacl.hash(d);
+  const h2 = new nacl.HashState().update(d).finish();
+
+  const s = new nacl.HashState();
+  for (let i = 0; i < n; i++) {
+    const b = new Uint8Array(1);
+    b[0] = d[i];
+    s.update(b);
+  }
+
+  const h3 = s.finish();
+
+  t.deepEqual(encodeCrock(h1), encodeCrock(h2));
+  t.deepEqual(encodeCrock(h1), encodeCrock(h3));
+});
+
+test("incremental hashing #2", (t) => {
+  const n = 10;
+  const d = nacl.randomBytes(n);
+
+  const h1 = nacl.hash(d);
+  const h2 = new nacl.HashState().update(d).finish();
+  const s = new nacl.HashState();
+  for (let i = 0; i < n; i++) {
+    const b = new Uint8Array(1);
+    b[0] = d[i];
+    s.update(b);
+  }
+
+  const h3 = s.finish();
+
+  t.deepEqual(encodeCrock(h1), encodeCrock(h3));
+  t.deepEqual(encodeCrock(h1), encodeCrock(h2));
+});
\ No newline at end of file
diff --git a/src/crypto/talerCrypto.ts b/src/crypto/talerCrypto.ts
index 0a36f0fe4..b754b0c57 100644
--- a/src/crypto/talerCrypto.ts
+++ b/src/crypto/talerCrypto.ts
@@ -18,9 +18,9 @@
  * Native implementation of GNU Taler crypto.
  */
 
-import nacl = require("./nacl-fast");
+import nacl = require("./primitives/nacl-fast");
 import bigint from "big-integer";
-import { kdf } from "./kdf";
+import { kdf } from "./primitives/kdf";
 
 export function getRandomBytes(n: number): Uint8Array {
   return nacl.randomBytes(n);
@@ -123,7 +123,7 @@ export function decodeCrock(encoded: string): Uint8Array {
 }
 
 export function eddsaGetPublic(eddsaPriv: Uint8Array): Uint8Array {
-  const pair = nacl.sign_keyPair_fromSeed(eddsaPriv); 
+  const pair = nacl.sign_keyPair_fromSeed(eddsaPriv);
   return pair.publicKey;
 }
 
@@ -131,7 +131,10 @@ export function ecdheGetPublic(ecdhePriv: Uint8Array): Uint8Array {
   return nacl.scalarMult_base(ecdhePriv);
 }
 
-export function keyExchangeEddsaEcdhe(eddsaPriv: Uint8Array, ecdhePub: Uint8Array): Uint8Array {
+export function keyExchangeEddsaEcdhe(
+  eddsaPriv: Uint8Array,
+  ecdhePub: Uint8Array,
+): Uint8Array {
   const ph = nacl.hash(eddsaPriv);
   const a = new Uint8Array(32);
   for (let i = 0; i < 32; i++) {
@@ -141,7 +144,10 @@ export function keyExchangeEddsaEcdhe(eddsaPriv: Uint8Array, ecdhePub: Uint8Arra
   return nacl.hash(x);
 }
 
-export function keyExchangeEcdheEddsa(ecdhePriv: Uint8Array, eddsaPub: Uint8Array): Uint8Array {
+export function keyExchangeEcdheEddsa(
+  ecdhePriv: Uint8Array,
+  eddsaPub: Uint8Array,
+): Uint8Array {
   const curve25519Pub = nacl.sign_ed25519_pk_to_curve25519(eddsaPub);
   const x = nacl.scalarMult(ecdhePriv, curve25519Pub);
   return nacl.hash(x);
@@ -172,8 +178,8 @@ function kdfMod(
   while (true) {
     const ctx = new Uint8Array(info.byteLength + 2);
     ctx.set(info, 0);
-    ctx[ctx.length - 2] = (counter >>> 8) & 0xFF;
-    ctx[ctx.length - 1] = counter & 0xFF;
+    ctx[ctx.length - 2] = (counter >>> 8) & 0xff;
+    ctx[ctx.length - 1] = counter & 0xff;
     const buf = kdf(buflen, ikm, salt, ctx);
     const arr = Array.from(buf);
     arr[0] = arr[0] & mask;
@@ -185,7 +191,7 @@ function kdfMod(
   }
 }
 
-function stringToBuf(s: string) {
+export function stringToBytes(s: string) {
   const te = new TextEncoder();
   return te.encode(s);
 }
@@ -194,9 +200,12 @@ function loadBigInt(arr: Uint8Array) {
   return bigint.fromArray(Array.from(arr), 256, false);
 }
 
-function rsaBlindingKeyDerive(rsaPub: RsaPub, bks: Uint8Array): bigint.BigInteger {
-  const salt = stringToBuf("Blinding KDF extrator HMAC key");
-  const info = stringToBuf("Blinding KDF");
+function rsaBlindingKeyDerive(
+  rsaPub: RsaPub,
+  bks: Uint8Array,
+): bigint.BigInteger {
+  const salt = stringToBytes("Blinding KDF extrator HMAC key");
+  const info = stringToBytes("Blinding KDF");
   return kdfMod(rsaPub.N, bks, salt, info);
 }
 
@@ -206,7 +215,7 @@ function rsaBlindingKeyDerive(rsaPub: RsaPub, bks: Uint8Array): bigint.BigIntege
  * Assuming n is an RSA modulous and r is generated using a call to
  * GNUNET_CRYPTO_kdf_mod_mpi, if gcd(r,n) != 1 then n must be a
  * malicious RSA key designed to deanomize the user.
- * 
+ *
  * @param r KDF result
  * @param n RSA modulus of the public key
  */
@@ -218,7 +227,7 @@ function rsaGcdValidate(r: bigint.BigInteger, n: bigint.BigInteger) {
 }
 
 function rsaFullDomainHash(hm: Uint8Array, rsaPub: RsaPub): bigint.BigInteger {
-  const info = stringToBuf("RSA-FDA FTpsW!");
+  const info = stringToBytes("RSA-FDA FTpsW!");
   const salt = rsaPubEncode(rsaPub);
   const r = kdfMod(rsaPub.N, hm, salt, info);
   rsaGcdValidate(r, rsaPub.N);
@@ -228,12 +237,15 @@ function rsaFullDomainHash(hm: Uint8Array, rsaPub: RsaPub): bigint.BigInteger {
 function rsaPubDecode(rsaPub: Uint8Array): RsaPub {
   const modulusLength = (rsaPub[0] << 8) | rsaPub[1];
   const exponentLength = (rsaPub[2] << 8) | rsaPub[3];
-  const modulus = rsaPub.slice(4, 4 + modulusLength)
-  const exponent = rsaPub.slice(4 + modulusLength, 4 + modulusLength + exponentLength);
+  const modulus = rsaPub.slice(4, 4 + modulusLength);
+  const exponent = rsaPub.slice(
+    4 + modulusLength,
+    4 + modulusLength + exponentLength,
+  );
   const res = {
     N: loadBigInt(modulus),
     e: loadBigInt(exponent),
-  }
+  };
   return res;
 }
 
@@ -241,16 +253,20 @@ function rsaPubEncode(rsaPub: RsaPub): Uint8Array {
   const mb = rsaPub.N.toArray(256).value;
   const eb = rsaPub.e.toArray(256).value;
   const out = new Uint8Array(4 + mb.length + eb.length);
-  out[0] = (mb.length >>> 8) & 0xFF;
-  out[1] = mb.length & 0xFF;
-  out[2] = (eb.length >>> 8) & 0xFF;
-  out[3] = eb.length & 0xFF;
+  out[0] = (mb.length >>> 8) & 0xff;
+  out[1] = mb.length & 0xff;
+  out[2] = (eb.length >>> 8) & 0xff;
+  out[3] = eb.length & 0xff;
   out.set(mb, 4);
   out.set(eb, 4 + mb.length);
   return out;
 }
 
-export function rsaBlind(hm: Uint8Array, bks: Uint8Array, rsaPubEnc: Uint8Array): Uint8Array {
+export function rsaBlind(
+  hm: Uint8Array,
+  bks: Uint8Array,
+  rsaPubEnc: Uint8Array,
+): Uint8Array {
   const rsaPub = rsaPubDecode(rsaPubEnc);
   const data = rsaFullDomainHash(hm, rsaPub);
   const r = rsaBlindingKeyDerive(rsaPub, bks);
@@ -259,7 +275,11 @@ export function rsaBlind(hm: Uint8Array, bks: Uint8Array, rsaPubEnc: Uint8Array)
   return new Uint8Array(bm.toArray(256).value);
 }
 
-export function rsaUnblind(sig: Uint8Array, rsaPubEnc: Uint8Array, bks: Uint8Array): Uint8Array {
+export function rsaUnblind(
+  sig: Uint8Array,
+  rsaPubEnc: Uint8Array,
+  bks: Uint8Array,
+): Uint8Array {
   const rsaPub = rsaPubDecode(rsaPubEnc);
   const blinded_s = loadBigInt(sig);
   const r = rsaBlindingKeyDerive(rsaPub, bks);
@@ -268,10 +288,86 @@ export function rsaUnblind(sig: Uint8Array, rsaPubEnc: Uint8Array, bks: Uint8Arr
   return new Uint8Array(s.toArray(256).value);
 }
 
-export function rsaVerify(hm: Uint8Array, rsaSig: Uint8Array, rsaPubEnc: Uint8Array): boolean {
+export function rsaVerify(
+  hm: Uint8Array,
+  rsaSig: Uint8Array,
+  rsaPubEnc: Uint8Array,
+): boolean {
   const rsaPub = rsaPubDecode(rsaPubEnc);
   const d = rsaFullDomainHash(hm, rsaPub);
   const sig = loadBigInt(rsaSig);
   const sig_e = sig.modPow(rsaPub.e, rsaPub.N);
   return sig_e.equals(d);
-}
\ No newline at end of file
+}
+
+export interface EddsaKeyPair {
+  eddsaPub: Uint8Array;
+  eddsaPriv: Uint8Array;
+}
+
+export interface EcdheKeyPair {
+  ecdhePub: Uint8Array;
+  ecdhePriv: Uint8Array;
+}
+
+export function createEddsaKeyPair(): EddsaKeyPair {
+  const eddsaPriv = nacl.randomBytes(32);
+  const eddsaPub = eddsaGetPublic(eddsaPriv);
+  return { eddsaPriv, eddsaPub };
+}
+
+export function createEcdheKeyPair(): EcdheKeyPair {
+  const ecdhePriv = nacl.randomBytes(32);
+  const ecdhePub = ecdheGetPublic(ecdhePriv);
+  return { ecdhePriv, ecdhePub };
+}
+
+export function createBlindingKeySecret(): Uint8Array {
+  return nacl.randomBytes(32);
+}
+
+export function hash(d: Uint8Array): Uint8Array {
+  return nacl.hash(d);
+}
+
+export function eddsaSign(msg: Uint8Array, eddsaPriv: Uint8Array): Uint8Array {
+  const pair = nacl.sign_keyPair_fromSeed(eddsaPriv);
+  return nacl.sign_detached(msg, pair.secretKey);
+}
+
+export function eddsaVerify(
+  msg: Uint8Array,
+  sig: Uint8Array,
+  eddsaPub: Uint8Array,
+): boolean {
+  return nacl.sign_detached_verify(msg, sig, eddsaPub);
+}
+
+export function createHashContext(): nacl.HashState {
+  return new nacl.HashState();
+}
+
+export interface FreshCoin {
+  coinPub: Uint8Array;
+  coinPriv: Uint8Array;
+  bks: Uint8Array;
+}
+
+export function setupRefreshPlanchet(
+  secretSeed: Uint8Array,
+  coinNumber: number,
+): FreshCoin {
+  const info = stringToBytes("taler-coin-derivation");
+  const saltArrBuf = new ArrayBuffer(4);
+  const salt = new Uint8Array(saltArrBuf);
+  const saltDataView = new DataView(saltArrBuf);
+  saltDataView.setUint32(0, coinNumber);
+  const out = kdf(64, secretSeed, salt, info);
+  const coinPriv = out.slice(0, 32);
+  const bks = out.slice(32, 64);
+  return {
+    bks,
+    coinPriv,
+    coinPub: eddsaGetPublic(coinPriv),
+  };
+}
diff --git a/src/dbTypes.ts b/src/dbTypes.ts
index 22d98ffac..bb4f5dbdf 100644
--- a/src/dbTypes.ts
+++ b/src/dbTypes.ts
@@ -283,26 +283,26 @@ export class DenominationRecord {
   /**
    * Validity start date of the denomination.
    */
-  @Checkable.String()
-  stampStart: string;
+  @Checkable.Value(() => Timestamp)
+  stampStart: Timestamp;
 
   /**
    * Date after which the currency can't be withdrawn anymore.
    */
-  @Checkable.String()
-  stampExpireWithdraw: string;
+  @Checkable.Value(() => Timestamp)
+  stampExpireWithdraw: Timestamp;
 
   /**
    * Date after the denomination officially doesn't exist anymore.
    */
-  @Checkable.String()
-  stampExpireLegal: string;
+  @Checkable.Value(() => Timestamp)
+  stampExpireLegal: Timestamp;
 
   /**
    * Data after which coins of this denomination can't be deposited anymore.
    */
-  @Checkable.String()
-  stampExpireDeposit: string;
+  @Checkable.Value(() => Timestamp)
+  stampExpireDeposit: Timestamp;
 
   /**
    * Signature by the exchange's master key over the denomination
diff --git a/src/headless/helpers.ts b/src/headless/helpers.ts
index 5e06a2f25..a38ef1dbe 100644
--- a/src/headless/helpers.ts
+++ b/src/headless/helpers.ts
@@ -33,6 +33,7 @@ import * as amounts from "../amounts";
 import { Bank } from "./bank";
 
 import fs = require("fs");
+import { NodeCryptoWorkerFactory } from "../crypto/nodeProcessWorker";
 
 const enableTracing = false;
 
@@ -188,14 +189,16 @@ export async function getDefaultNodeWallet(
     myUnsupportedUpgrade,
   );
 
+  const worker = new SynchronousCryptoWorkerFactory();
+  //const worker = new NodeCryptoWorkerFactory();
+
   return new Wallet(
     myDb,
     myHttpLib,
     myBadge,
     myNotifier,
-    new SynchronousCryptoWorkerFactory(),
+    worker,
   );
-  //const myWallet = new Wallet(myDb, myHttpLib, myBadge, myNotifier, new NodeCryptoWorkerFactory());
 }
 
 export async function withdrawTestBalance(
diff --git a/src/headless/taler-wallet-cli.ts b/src/headless/taler-wallet-cli.ts
index bec098aca..90c04dd97 100644
--- a/src/headless/taler-wallet-cli.ts
+++ b/src/headless/taler-wallet-cli.ts
@@ -353,7 +353,6 @@ testCli
     default: "TESTKUDOS:4",
   })
   .action(async args => {
-    console.log("parsed args", args);
     applyVerbose(args.wallet.verbose);
     let cmdObj = args.integrationtestCmd;
 
diff --git a/src/helpers.ts b/src/helpers.ts
index cfebf394f..1983cee9b 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -140,6 +140,17 @@ export function extractTalerStamp(stamp: string): Timestamp | undefined {
 }
 
 /**
+ * Extract a timestamp from a Taler timestamp string.
+ */
+export function extractTalerStampOrThrow(stamp: string): Timestamp {
+  const r = extractTalerStamp(stamp);
+  if (!r) {
+    throw Error("invalid time stamp");
+  }
+  return r;
+}
+
+/**
  * Check if a timestamp is in the right format.
  */
 export function timestampCheck(stamp: string): boolean {
diff --git a/src/talerTypes.ts b/src/talerTypes.ts
index ebb13f4a5..1e658d5be 100644
--- a/src/talerTypes.ts
+++ b/src/talerTypes.ts
@@ -388,10 +388,10 @@ export class ContractTerms {
   @Checkable.String(timestampCheck)
   refund_deadline: string;
 
-    /**
+  /**
    * Deadline for the wire transfer.
    */
-  @Checkable.String(timestampCheck)
+  @Checkable.String()
   wire_transfer_deadline: string;
 
   /**
diff --git a/src/wallet-test.ts b/src/wallet-test.ts
index bd0925ed0..86ddb5e73 100644
--- a/src/wallet-test.ts
+++ b/src/wallet-test.ts
@@ -59,10 +59,10 @@ function fakeCwd(current: string, value: string, feeDeposit: string): types.Coin
       feeWithdraw: a("EUR:0.0"),
       isOffered: true,
       masterSig: "(mock)",
-      stampExpireDeposit: "(mock)",
-      stampExpireLegal: "(mock)",
-      stampExpireWithdraw: "(mock)",
-      stampStart: "(mock)",
+      stampExpireDeposit: { t_ms: 0 },
+      stampExpireLegal: { t_ms: 0 },
+      stampExpireWithdraw: { t_ms: 0 },
+      stampStart: { t_ms: 0 },
       status: dbTypes.DenominationStatus.VerifiedGood,
       value: a(value),
     },
diff --git a/src/wallet.ts b/src/wallet.ts
index 58bb6b8c3..f1d7be5e5 100644
--- a/src/wallet.ts
+++ b/src/wallet.ts
@@ -30,6 +30,7 @@ import {
   getTalerStampSec,
   strcmp,
   extractTalerStamp,
+  extractTalerStampOrThrow,
 } from "./helpers";
 import { HttpRequestLibrary } from "./http";
 import * as LibtoolVersion from "./libtoolVersion";
@@ -163,20 +164,10 @@ const builtinCurrencies: CurrencyRecord[] = [
 ];
 
 function isWithdrawableDenom(d: DenominationRecord) {
-  const nowSec = new Date().getTime() / 1000;
-  const stampWithdrawSec = getTalerStampSec(d.stampExpireWithdraw);
-  if (stampWithdrawSec === null) {
-    return false;
-  }
-  const stampStartSec = getTalerStampSec(d.stampStart);
-  if (stampStartSec === null) {
-    return false;
-  }
-  // Withdraw if still possible to withdraw within a minute
-  if (stampWithdrawSec + 60 > nowSec && nowSec >= stampStartSec) {
-    return true;
-  }
-  return false;
+  const now = getTimestampNow();
+  const started = now.t_ms >= d.stampStart.t_ms;
+  const stillOkay = d.stampExpireWithdraw.t_ms + (60 * 1000) > now.t_ms;
+  return started && stillOkay;
 }
 
 interface SelectPayCoinsResult {
@@ -1374,6 +1365,7 @@ export class Wallet {
         denom.feeWithdraw,
       );
       if (x.saturated) {
+        // FIXME!!!!
         console.error("database inconsistent");
         throw TransactionAbort;
       }
@@ -1891,10 +1883,10 @@ export class Wallet {
 
     const { isTrusted, isAudited } = await this.getExchangeTrust(exchangeInfo);
 
-    let earliestDepositExpiration = Infinity;
-    for (const denom of selectedDenoms) {
-      const expireDeposit = getTalerStampSec(denom.stampExpireDeposit)!;
-      if (expireDeposit < earliestDepositExpiration) {
+    let earliestDepositExpiration = selectedDenoms[0].stampExpireDeposit;
+    for (let i = 1; i < selectedDenoms.length; i++) {
+      const expireDeposit = selectedDenoms[i].stampExpireDeposit;
+      if (expireDeposit.t_ms < earliestDepositExpiration.t_ms) {
         earliestDepositExpiration = expireDeposit;
       }
     }
@@ -2653,6 +2645,7 @@ export class Wallet {
       resp = await this.http.postJson(reqUrl.href(), req);
     } catch (e) {
       console.error("got error during /refresh/reveal request");
+      console.error(e);
       return;
     }
 
@@ -3137,10 +3130,10 @@ export class Wallet {
       feeWithdraw: Amounts.parseOrThrow(denomIn.fee_withdraw),
       isOffered: true,
       masterSig: denomIn.master_sig,
-      stampExpireDeposit: denomIn.stamp_expire_deposit,
-      stampExpireLegal: denomIn.stamp_expire_legal,
-      stampExpireWithdraw: denomIn.stamp_expire_withdraw,
-      stampStart: denomIn.stamp_start,
+      stampExpireDeposit: extractTalerStampOrThrow(denomIn.stamp_expire_deposit),
+      stampExpireLegal: extractTalerStampOrThrow(denomIn.stamp_expire_legal),
+      stampExpireWithdraw: extractTalerStampOrThrow(denomIn.stamp_expire_withdraw),
+      stampStart: extractTalerStampOrThrow(denomIn.stamp_start),
       status: DenominationStatus.Unverified,
       value: Amounts.parseOrThrow(denomIn.value),
     };
diff --git a/src/walletTypes.ts b/src/walletTypes.ts
index a11da029f..b971e300d 100644
--- a/src/walletTypes.ts
+++ b/src/walletTypes.ts
@@ -113,7 +113,7 @@ export interface ReserveCreationInfo {
   /**
    * The earliest deposit expiration of the selected coins.
    */
-  earliestDepositExpiration: number;
+  earliestDepositExpiration: Timestamp;
 
   /**
    * Number of currently offered denominations.
@@ -591,11 +591,15 @@ export interface HistoryQuery {
   level: number;
 }
 
-export interface Timestamp {
+@Checkable.Class()
+export class Timestamp {
   /**
    * Timestamp in milliseconds.
    */
+  @Checkable.Number()
   t_ms: number;
+
+  static checked: (obj: any) => Timestamp;
 }
 
 export interface Duration {
diff --git a/src/webex/renderHtml.tsx b/src/webex/renderHtml.tsx
index c2fdb1f14..42bcdbabc 100644
--- a/src/webex/renderHtml.tsx
+++ b/src/webex/renderHtml.tsx
@@ -240,7 +240,7 @@ function FeeDetailsView(props: {
         {i18n.str`Rounding loss:`} {overhead}
       </p>
       <p>{i18n.str`Earliest expiration (for deposit): ${moment
-        .unix(rci.earliestDepositExpiration)
+        .unix(rci.earliestDepositExpiration.t_ms / 1000)
         .fromNow()}`}</p>
       <h3>Coin Fees</h3>
       <div style={{ overflow: "auto" }}>