Simplify loading of the emscripten lib.

This removes an ugly hack and makes it possible to access the emscripten
compiled library from within nodejs test cases more easily.

1 files changed, 1392 insertions, 0 deletions

diff --git a/src/crypto/emscInterface.ts b/src/crypto/emscInterface.ts
new file mode 100644
index 000000000..52c6c965e
--- /dev/null
+++ b/src/crypto/emscInterface.ts
@@ -0,0 +1,1392 @@
+/*
+ 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 "../types";
+import {getLib, EmscFunGen} from "./emscLoader";
+
+
+const emscLib = getLib();
+
+
+/**
+ * Size of a native pointer.  Must match the size
+ * use when compiling via emscripten.
+ */
+const PTR_SIZE = 4;
+
+const GNUNET_OK = 1;
+const GNUNET_YES = 1;
+const GNUNET_NO = 0;
+const GNUNET_SYSERR = -1;
+
+
+/**
+ * Get an emscripten-compiled function.
+ */
+const getEmsc: EmscFunGen = (name: string, ret: any, argTypes: any[]) => {
+  return (...args: any[]) => {
+    return emscLib.ccall(name, ret, argTypes, args);
+  }
+};
+
+
+/**
+ * Wrapped emscripten functions that do not allocate any memory.
+ */
+const emsc = {
+  free: (ptr: number) => emscLib._free(ptr),
+  get_value: getEmsc("TALER_WR_get_value",
+                     "number",
+                     ["number"]),
+  get_fraction: getEmsc("TALER_WR_get_fraction",
+                        "number",
+                        ["number"]),
+  get_currency: getEmsc("TALER_WR_get_currency",
+                        "string",
+                        ["number"]),
+  amount_add: getEmsc("TALER_amount_add",
+                      "number",
+                      ["number", "number", "number"]),
+  amount_subtract: getEmsc("TALER_amount_subtract",
+                           "number",
+                           ["number", "number", "number"]),
+  amount_normalize: getEmsc("TALER_amount_normalize",
+                            "void",
+                            ["number"]),
+  amount_get_zero: getEmsc("TALER_amount_get_zero",
+                           "number",
+                           ["string", "number"]),
+  amount_cmp: getEmsc("TALER_amount_cmp",
+                      "number",
+                      ["number", "number"]),
+  amount_hton: getEmsc("TALER_amount_hton",
+                       "void",
+                       ["number", "number"]),
+  amount_ntoh: getEmsc("TALER_amount_ntoh",
+                       "void",
+                       ["number", "number"]),
+  hash: getEmsc("GNUNET_CRYPTO_hash",
+                "void",
+                ["number", "number", "number"]),
+  memmove: getEmsc("memmove",
+                   "number",
+                   ["number", "number", "number"]),
+  rsa_public_key_free: getEmsc("GNUNET_CRYPTO_rsa_public_key_free",
+                               "void",
+                               ["number"]),
+  rsa_signature_free: getEmsc("GNUNET_CRYPTO_rsa_signature_free",
+                              "void",
+                              ["number"]),
+  string_to_data: getEmsc("GNUNET_STRINGS_string_to_data",
+                          "number",
+                          ["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"]),
+  hash_create_random: getEmsc("GNUNET_CRYPTO_hash_create_random",
+                              "void",
+                              ["number", "number"]),
+  rsa_blinding_key_destroy: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_free",
+                                    "void",
+                                    ["number"]),
+  random_block: getEmsc("GNUNET_CRYPTO_random_block",
+                        "void",
+                        ["number", "number", "number"]),
+  hash_context_abort: getEmsc("GNUNET_CRYPTO_hash_context_abort",
+                              "void",
+                              ["number"]),
+  hash_context_read: getEmsc("GNUNET_CRYPTO_hash_context_read",
+                             "void",
+                             ["number", "number", "number"]),
+  hash_context_finish: getEmsc("GNUNET_CRYPTO_hash_context_finish",
+                               "void",
+                               ["number", "number"]),
+  ecdh_eddsa: getEmsc("GNUNET_CRYPTO_ecdh_eddsa",
+                      "number",
+                     ["number", "number", "number"]),
+
+  setup_fresh_coin: getEmsc(
+    "TALER_setup_fresh_coin",
+    "void",
+    ["number", "number", "number"]),
+};
+
+
+/**
+ * Emscripten functions that allocate memory.
+ */
+const emscAlloc = {
+  get_amount: getEmsc("TALER_WRALL_get_amount",
+                      "number",
+                      ["number", "number", "number", "string"]),
+  eddsa_key_create: getEmsc("GNUNET_CRYPTO_eddsa_key_create",
+                            "number", []),
+  ecdsa_key_create: getEmsc("GNUNET_CRYPTO_ecdsa_key_create",
+                            "number", []),
+  ecdhe_key_create: getEmsc("GNUNET_CRYPTO_ecdhe_key_create",
+                            "number", []),
+  eddsa_public_key_from_private: getEmsc(
+    "TALER_WRALL_eddsa_public_key_from_private",
+    "number",
+    ["number"]),
+  ecdsa_public_key_from_private: getEmsc(
+    "TALER_WRALL_ecdsa_public_key_from_private",
+    "number",
+    ["number"]),
+  ecdhe_public_key_from_private: getEmsc(
+    "TALER_WRALL_ecdhe_public_key_from_private",
+    "number",
+    ["number"]),
+  data_to_string_alloc: getEmsc("GNUNET_STRINGS_data_to_string_alloc",
+                                "number",
+                                ["number", "number"]),
+  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_encode: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_encode",
+                                   "number",
+                                   ["number", "number"]),
+  rsa_signature_encode: getEmsc("GNUNET_CRYPTO_rsa_signature_encode",
+                                "number",
+                                ["number", "number"]),
+  rsa_blinding_key_decode: getEmsc("GNUNET_CRYPTO_rsa_blinding_key_decode",
+                                   "number",
+                                   ["number", "number"]),
+  rsa_public_key_decode: getEmsc("GNUNET_CRYPTO_rsa_public_key_decode",
+                                 "number",
+                                 ["number", "number"]),
+  rsa_signature_decode: getEmsc("GNUNET_CRYPTO_rsa_signature_decode",
+                                "number",
+                                ["number", "number"]),
+  rsa_public_key_encode: getEmsc("GNUNET_CRYPTO_rsa_public_key_encode",
+                                 "number",
+                                 ["number", "number"]),
+  rsa_unblind: getEmsc("GNUNET_CRYPTO_rsa_unblind",
+                       "number",
+                       ["number", "number", "number"]),
+  hash_context_start: getEmsc("GNUNET_CRYPTO_hash_context_start",
+                              "number",
+                              []),
+  malloc: (size: number) => emscLib._malloc(size),
+};
+
+
+/**
+ * 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,
+}
+
+
+/**
+ * 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() {
+    this.hashContextPtr = emscAlloc.hash_context_start();
+  }
+
+  /**
+   * Add data to be hashed.
+   */
+  read(obj: PackedArenaObject): void {
+    if (!this.hashContextPtr) {
+      throw Error("assertion failed");
+    }
+    emsc.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();
+    emsc.hash_context_finish(this.hashContextPtr, h.nativePtr);
+  }
+
+  /**
+   * Abort hashing without computing the result.
+   */
+  destroy(): void {
+    if (this.hashContextPtr) {
+      emsc.hash_context_abort(this.hashContextPtr);
+    }
+    this.hashContextPtr = undefined;
+  }
+}
+
+
+/**
+ * Arena object that points to an allocaed 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) {
+      emsc.free(this.nativePtr);
+      this._nativePtr = undefined;
+    }
+  }
+
+  constructor(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 = emscAlloc.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 {
+  heap: Array<ArenaObject>;
+
+  constructor() {
+    this.heap = [];
+  }
+
+  put(obj: ArenaObject) {
+    this.heap.push(obj);
+  }
+
+  destroy() {
+    for (let 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();
+    });
+  }
+}
+
+let arenaStack: Arena[] = [];
+arenaStack.push(new SyncArena());
+
+
+/**
+ * Representation of monetary value in a given currency.
+ */
+export class Amount extends MallocArenaObject {
+  constructor(args?: AmountJson, arena?: Arena) {
+    super(arena);
+    if (args) {
+      this.nativePtr = emscAlloc.get_amount(args.value,
+                                            0,
+                                            args.fraction,
+                                            args.currency);
+    } else {
+      this.nativePtr = emscAlloc.get_amount(0, 0, 0, "");
+    }
+  }
+
+  static getZero(currency: string, a?: Arena): Amount {
+    let am = new Amount(undefined, a);
+    let r = emsc.amount_get_zero(currency, am.nativePtr);
+    if (r != GNUNET_OK) {
+      throw Error("invalid currency");
+    }
+    return am;
+  }
+
+
+  toNbo(a?: Arena): AmountNbo {
+    let x = new AmountNbo(a);
+    x.alloc();
+    emsc.amount_hton(x.nativePtr, this.nativePtr);
+    return x;
+  }
+
+  fromNbo(nbo: AmountNbo): void {
+    emsc.amount_ntoh(this.nativePtr, nbo.nativePtr);
+  }
+
+  get value() {
+    return emsc.get_value(this.nativePtr);
+  }
+
+  get fraction() {
+    return emsc.get_fraction(this.nativePtr);
+  }
+
+  get currency(): String {
+    return emsc.get_currency(this.nativePtr);
+  }
+
+  toJson(): AmountJson {
+    return {
+      value: emsc.get_value(this.nativePtr),
+      fraction: emsc.get_fraction(this.nativePtr),
+      currency: emsc.get_currency(this.nativePtr)
+    };
+  }
+
+  /**
+   * Add an amount to this amount.
+   */
+  add(a: Amount) {
+    let res = emsc.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
+    let res = emsc.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 emsc.amount_cmp(this.nativePtr, a.nativePtr);
+  }
+
+  normalize() {
+    emsc.amount_normalize(this.nativePtr);
+  }
+}
+
+
+/**
+ * Count the UTF-8 characters in a JavaScript string.
+ */
+function countUtf8Bytes(str: string): number {
+  var s = str.length;
+  // JavaScript strings are UTF-16 arrays
+  for (let i = str.length - 1; i >= 0; i--) {
+    var 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(a?: Arena) {
+    super(a);
+  }
+
+  randomize(qual: RandomQuality = RandomQuality.STRONG): void {
+    emsc.random_block(qual, this.nativePtr, this.size());
+  }
+
+  toCrock(): string {
+    var d = emscAlloc.data_to_string_alloc(this.nativePtr, this.size());
+    var s = emscLib.Pointer_stringify(d);
+    emsc.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.
+    let buf = ByteArray.fromStringWithNull(s);
+    let res = emsc.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 = emscAlloc.malloc(this.size());
+    }
+  }
+
+  hash(): HashCode {
+    var x = new HashCode();
+    x.alloc();
+    emsc.hash(this.nativePtr, this.size(), x.nativePtr);
+    return x;
+  }
+
+  hexdump() {
+    let bytes: string[] = [];
+    for (let i = 0; i < this.size(); i++) {
+      let b = emscLib.getValue(this.nativePtr + i, "i8");
+      b = (b + 256) % 256;
+      bytes.push("0".concat(b.toString(16)).slice(-2));
+    }
+    let 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 {
+    let a = new SimpleArena();
+    let am = new Amount(undefined, a);
+    am.fromNbo(this);
+    let json = am.toJson();
+    a.destroy();
+    return json;
+  }
+}
+
+
+/**
+ * Create a packed arena object from the base32 crockford encoding.
+ */
+function fromCrock<T extends PackedArenaObject>(s: string, ctor: Ctor<T>): T {
+  let x: T = new ctor();
+  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>(s: string, ctor: Ctor<T>, decodeFn: (p: number, s: number) => number): T {
+  let obj = new ctor();
+  let buf = ByteArray.fromCrock(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 {
+  let ptr = emscAlloc.malloc(PTR_SIZE);
+  let len = encodeFn(obj.nativePtr, ptr);
+  let res = new ByteArray(len, undefined, arena);
+  res.nativePtr = emscLib.getValue(ptr, '*');
+  emsc.free(ptr);
+  return res;
+}
+
+
+/**
+ * Private EdDSA key.
+ */
+export class EddsaPrivateKey extends PackedArenaObject {
+  static create(a?: Arena): EddsaPrivateKey {
+    let obj = new EddsaPrivateKey(a);
+    obj.nativePtr = emscAlloc.eddsa_key_create();
+    return obj;
+  }
+
+  size() {
+    return 32;
+  }
+
+  getPublicKey(a?: Arena): EddsaPublicKey {
+    let obj = new EddsaPublicKey(a);
+    obj.nativePtr = emscAlloc.eddsa_public_key_from_private(this.nativePtr);
+    return obj;
+  }
+
+  static fromCrock(s: string): EddsaPrivateKey {
+    return fromCrock(s, this);
+  }
+}
+
+
+export class EcdsaPrivateKey extends PackedArenaObject {
+  static create(a?: Arena): EcdsaPrivateKey {
+    let obj = new EcdsaPrivateKey(a);
+    obj.nativePtr = emscAlloc.ecdsa_key_create();
+    return obj;
+  }
+
+  size() {
+    return 32;
+  }
+
+  getPublicKey(a?: Arena): EcdsaPublicKey {
+    let obj = new EcdsaPublicKey(a);
+    obj.nativePtr = emscAlloc.ecdsa_public_key_from_private(this.nativePtr);
+    return obj;
+  }
+
+  static fromCrock(s: string): EcdsaPrivateKey {
+    return fromCrock(s, this);
+  }
+}
+
+
+export class EcdhePrivateKey extends PackedArenaObject {
+  static create(a?: Arena): EcdhePrivateKey {
+    let obj = new EcdhePrivateKey(a);
+    obj.nativePtr = emscAlloc.ecdhe_key_create();
+    return obj;
+  }
+
+  size() {
+    return 32;
+  }
+
+  getPublicKey(a?: Arena): EcdhePublicKey {
+    let obj = new EcdhePublicKey(a);
+    obj.nativePtr = emscAlloc.ecdhe_public_key_from_private(this.nativePtr);
+    return obj;
+  }
+
+  static fromCrock(s: string): EcdhePrivateKey {
+    return fromCrock(s, this);
+  }
+}
+
+
+/**
+ * Constructor for a given type.
+ */
+interface Ctor<T> {
+  new(): T
+}
+
+
+export class EddsaPublicKey extends PackedArenaObject {
+  size() {
+    return 32;
+  }
+
+  static fromCrock(s: string): EddsaPublicKey {
+    return fromCrock(s, this);
+  }
+}
+
+export class EcdsaPublicKey extends PackedArenaObject {
+  size() {
+    return 32;
+  }
+
+  static fromCrock(s: string): EcdsaPublicKey {
+    return fromCrock(s, this);
+  }
+}
+
+
+export class EcdhePublicKey extends PackedArenaObject {
+  size() {
+    return 32;
+  }
+
+  static fromCrock(s: string): EcdhePublicKey {
+    return fromCrock(s, this);
+  }
+}
+
+export class RsaBlindingKeySecret extends PackedArenaObject {
+  size() {
+    return 32;
+  }
+
+  /**
+   * Create a random blinding key secret.
+   */
+  static create(a?: Arena): RsaBlindingKeySecret {
+    let o = new RsaBlindingKeySecret(a);
+    o.alloc();
+    o.randomize();
+    return o;
+  }
+
+  static fromCrock(s: string): RsaBlindingKeySecret {
+    return fromCrock(s, this);
+  }
+}
+
+
+export class HashCode extends PackedArenaObject {
+  size() {
+    return 64;
+  }
+
+  static fromCrock(s: string): HashCode {
+    return fromCrock(s, this);
+  }
+
+  random(qual: RandomQuality = RandomQuality.STRONG) {
+    this.alloc();
+    emsc.hash_create_random(qual, this.nativePtr);
+  }
+}
+
+
+export class ByteArray extends PackedArenaObject {
+  private allocatedSize: number;
+
+  size() {
+    return this.allocatedSize;
+  }
+
+  constructor(desiredSize: number, init?: number, a?: Arena) {
+    super(a);
+    if (init === undefined) {
+      this.nativePtr = emscAlloc.malloc(desiredSize);
+    } else {
+      this.nativePtr = init;
+    }
+    this.allocatedSize = desiredSize;
+  }
+
+  static fromStringWithoutNull(s: string, a?: Arena): ByteArray {
+    // UTF-8 bytes, including 0-terminator
+    let terminatedByteLength = countUtf8Bytes(s) + 1;
+    let hstr = emscAlloc.malloc(terminatedByteLength);
+    emscLib.stringToUTF8(s, hstr, terminatedByteLength);
+    return new ByteArray(terminatedByteLength - 1, hstr, a);
+  }
+
+  static fromStringWithNull(s: string, a?: Arena): ByteArray {
+    // UTF-8 bytes, including 0-terminator
+    let terminatedByteLength = countUtf8Bytes(s) + 1;
+    let hstr = emscAlloc.malloc(terminatedByteLength);
+    emscLib.stringToUTF8(s, hstr, terminatedByteLength);
+    return new ByteArray(terminatedByteLength, hstr, a);
+  }
+
+  static fromCrock(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
+    let byteLength = countUtf8Bytes(s);
+    let hstr = emscAlloc.malloc(byteLength + 1);
+    emscLib.stringToUTF8(s, hstr, byteLength + 1);
+    let decodedLen = Math.floor((byteLength * 5) / 8);
+    let ba = new ByteArray(decodedLen, undefined, a);
+    let res = emsc.string_to_data(hstr, byteLength, ba.nativePtr, decodedLen);
+    emsc.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;
+  }
+
+  payloadSize: number;
+
+  constructor(purpose: SignaturePurpose,
+              payload: PackedArenaObject,
+              a?: Arena) {
+    super(a);
+    this.nativePtr = emscAlloc.purpose_create(purpose,
+                                              payload.nativePtr,
+                                              payload.size());
+    this.payloadSize = payload.size();
+  }
+}
+
+
+abstract class SignatureStruct {
+  abstract fieldTypes(): Array<any>;
+
+  abstract purpose(): SignaturePurpose;
+
+  private members: any = {};
+
+  constructor(x: { [name: string]: any }) {
+    for (let k in x) {
+      this.set(k, x[k]);
+    }
+  }
+
+  toPurpose(a?: Arena): EccSignaturePurpose {
+    let totalSize = 0;
+    for (let f of this.fieldTypes()) {
+      let name = f[0];
+      let member = this.members[name];
+      if (!member) {
+        throw Error(`Member ${name} not set`);
+      }
+      totalSize += member.size();
+    }
+
+    let buf = emscAlloc.malloc(totalSize);
+    let ptr = buf;
+    for (let f of this.fieldTypes()) {
+      let name = f[0];
+      let member = this.members[name];
+      let size = member.size();
+      emsc.memmove(ptr, member.nativePtr, size);
+      ptr += size;
+    }
+    let ba = new ByteArray(totalSize, buf, a);
+    return new EccSignaturePurpose(this.purpose(), ba);
+  }
+
+
+  toJson() {
+    let res: any = {};
+    for (let f of this.fieldTypes()) {
+      let name = f[0];
+      let 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) {
+    let typemap: any = {};
+    for (let 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;
+  }
+}
+
+
+// It's redundant, but more type safe.
+export interface WithdrawRequestPS_Args {
+  reserve_pub: EddsaPublicKey;
+  amount_with_fee: AmountNbo;
+  withdraw_fee: AmountNbo;
+  h_denomination_pub: HashCode;
+  h_coin_envelope: HashCode;
+}
+
+
+export class WithdrawRequestPS extends SignatureStruct {
+  constructor(w: WithdrawRequestPS_Args) {
+    super(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]
+    ];
+  }
+}
+
+
+export interface PaybackRequestPS_args {
+  coin_pub: EddsaPublicKey;
+  h_denom_pub: HashCode;
+  coin_blind: RsaBlindingKeySecret;
+}
+
+
+export class PaybackRequestPS extends SignatureStruct {
+  constructor(w: PaybackRequestPS_args) {
+    super(w);
+  }
+
+  purpose() {
+    return SignaturePurpose.WALLET_COIN_PAYBACK;
+  }
+
+  fieldTypes() {
+    return [
+      ["coin_pub", EddsaPublicKey],
+      ["h_denom_pub", HashCode],
+      ["coin_blind", RsaBlindingKeySecret],
+    ];
+  }
+}
+
+
+interface RefreshMeltCoinAffirmationPS_Args {
+  session_hash: HashCode;
+  amount_with_fee: AmountNbo;
+  melt_fee: AmountNbo;
+  coin_pub: EddsaPublicKey;
+}
+
+export class RefreshMeltCoinAffirmationPS extends SignatureStruct {
+
+  constructor(w: RefreshMeltCoinAffirmationPS_Args) {
+    super(w);
+  }
+
+  purpose() {
+    return SignaturePurpose.WALLET_COIN_MELT;
+  }
+
+  fieldTypes() {
+    return [
+      ["session_hash", HashCode],
+      ["amount_with_fee", AmountNbo],
+      ["melt_fee", AmountNbo],
+      ["coin_pub", EddsaPublicKey]
+    ];
+  }
+}
+
+
+interface MasterWireFeePS_Args {
+  h_wire_method: HashCode;
+  start_date: AbsoluteTimeNbo;
+  end_date: AbsoluteTimeNbo;
+  wire_fee: AmountNbo;
+  closing_fee: AmountNbo;
+}
+
+export class MasterWireFeePS extends SignatureStruct {
+  constructor(w: MasterWireFeePS_Args) {
+    super(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],
+    ];
+  }
+}
+
+
+export class AbsoluteTimeNbo extends PackedArenaObject {
+  static fromTalerString(s: string): AbsoluteTimeNbo {
+    let x = new AbsoluteTimeNbo();
+    x.alloc();
+    let r = /Date\(([0-9]+)\)/;
+    let m = r.exec(s);
+    if (!m || m.length != 2) {
+      throw Error();
+    }
+    let n = parseInt(m[1]) * 1000000;
+    // XXX: This only works up to 54 bit numbers.
+    set64(x.nativePtr, n);
+    return x;
+  }
+
+  static fromStampSeconds(stamp: number): AbsoluteTimeNbo {
+    let x = new AbsoluteTimeNbo();
+    x.alloc();
+    // XXX: This only works up to 54 bit numbers.
+    set64(x.nativePtr, stamp * 1000000);
+    return x;
+  }
+
+
+  size() {
+    return 8;
+  }
+}
+
+
+// XXX: This only works up to 54 bit numbers.
+function set64(p: number, n: number) {
+  for (let i = 0; i < 8; ++i) {
+    emscLib.setValue(p + (7 - i), n & 0xFF, "i8");
+    n = Math.floor(n / 256);
+  }
+}
+
+// XXX: This only works up to 54 bit numbers.
+function set32(p: number, n: number) {
+  for (let i = 0; i < 4; ++i) {
+    emscLib.setValue(p + (3 - i), n & 0xFF, "i8");
+    n = Math.floor(n / 256);
+  }
+}
+
+
+export class UInt64 extends PackedArenaObject {
+  static fromNumber(n: number): UInt64 {
+    let x = new UInt64();
+    x.alloc();
+    set64(x.nativePtr, n);
+    return x;
+  }
+
+  size() {
+    return 8;
+  }
+}
+
+
+export class UInt32 extends PackedArenaObject {
+  static fromNumber(n: number): UInt64 {
+    let x = new UInt32();
+    x.alloc();
+    set32(x.nativePtr, n);
+    return x;
+  }
+
+  size() {
+    return 4;
+  }
+}
+
+
+// It's redundant, but more type safe.
+export interface DepositRequestPS_Args {
+  h_contract: HashCode;
+  h_wire: HashCode;
+  timestamp: AbsoluteTimeNbo;
+  refund_deadline: AbsoluteTimeNbo;
+  amount_with_fee: AmountNbo;
+  deposit_fee: AmountNbo;
+  merchant: EddsaPublicKey;
+  coin_pub: EddsaPublicKey;
+}
+
+
+export class DepositRequestPS extends SignatureStruct {
+  constructor(w: DepositRequestPS_Args) {
+    super(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],
+    ];
+  }
+}
+
+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;
+}
+
+export class DenominationKeyValidityPS extends SignatureStruct {
+  constructor(w: DenominationKeyValidityPS_args) {
+    super(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]
+    ];
+  }
+}
+
+export interface PaymentSignaturePS_args {
+  contract_hash: HashCode;
+}
+
+export class PaymentSignaturePS extends SignatureStruct {
+  constructor(w: PaymentSignaturePS_args) {
+    super(w);
+  }
+
+  purpose() {
+    return SignaturePurpose.MERCHANT_PAYMENT_OK;
+  }
+
+  fieldTypes() {
+    return [
+      ["contract_hash", HashCode],
+    ];
+  }
+}
+
+
+export class RsaPublicKey extends MallocArenaObject {
+  static fromCrock(s: string): RsaPublicKey {
+    return fromCrockDecoded(s, this, emscAlloc.rsa_public_key_decode);
+  }
+
+  toCrock() {
+    return this.encode().toCrock();
+  }
+
+  destroy() {
+    emsc.rsa_public_key_free(this.nativePtr);
+    this.nativePtr = 0;
+  }
+
+  encode(arena?: Arena): ByteArray {
+    return encode(this, emscAlloc.rsa_public_key_encode);
+  }
+}
+
+
+export class EddsaSignature extends PackedArenaObject {
+  size() {
+    return 64;
+  }
+  static fromCrock(s: string): EddsaSignature {
+    return fromCrock(s, this);
+  }
+}
+
+
+export class RsaSignature extends MallocArenaObject {
+  static fromCrock(s: string, a?: Arena) {
+    return fromCrockDecoded(s, this, emscAlloc.rsa_signature_decode);
+  }
+
+  encode(arena?: Arena): ByteArray {
+    return encode(this, emscAlloc.rsa_signature_encode);
+  }
+
+  destroy() {
+    emsc.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 {
+  let buf_ptr_out = emscAlloc.malloc(PTR_SIZE);
+  let buf_size_out = emscAlloc.malloc(PTR_SIZE);
+  let res = emscAlloc.rsa_blind(hashCode.nativePtr,
+                                blindingKey.nativePtr,
+                                pkey.nativePtr,
+                                buf_ptr_out,
+                                buf_size_out);
+  let buf_ptr = emscLib.getValue(buf_ptr_out, '*');
+  let buf_size = emscLib.getValue(buf_size_out, '*');
+  emsc.free(buf_ptr_out);
+  emsc.free(buf_size_out);
+  if (res != GNUNET_OK) {
+    // malicious key
+    return null;
+  }
+  return new ByteArray(buf_size, buf_ptr, arena);
+}
+
+
+/**
+ * Sign data using EdDSA.
+ */
+export function eddsaSign(purpose: EccSignaturePurpose,
+                          priv: EddsaPrivateKey,
+                          a?: Arena): EddsaSignature {
+  let sig = new EddsaSignature(a);
+  sig.alloc();
+  let res = emsc.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 {
+  let r = emsc.eddsa_verify(purposeNum,
+                            verify.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 {
+  let x = new RsaSignature(a);
+  x.nativePtr = emscAlloc.rsa_unblind(sig.nativePtr,
+                                      bk.nativePtr,
+                                      pk.nativePtr);
+  return x;
+}
+
+
+type TransferSecretP = HashCode;
+
+export interface FreshCoin {
+  priv: EddsaPrivateKey;
+  blindingKey: RsaBlindingKeySecret;
+}
+
+/**
+ * Diffie-Hellman operation between an ECDHE private key
+ * and an EdDSA public key.
+ */
+export function ecdhEddsa(priv: EcdhePrivateKey,
+                          pub: EddsaPublicKey): HashCode {
+  let h = new HashCode();
+  h.alloc();
+  let res = emsc.ecdh_eddsa(priv.nativePtr, pub.nativePtr, h.nativePtr);
+  if (res != GNUNET_OK) {
+    throw Error("ecdh_eddsa failed");
+  }
+  return h;
+}
+
+
+/**
+ * Derive a fresh coin from the given seed.  Used during refreshing.
+ */
+export function setupFreshCoin(secretSeed: TransferSecretP,
+                               coinIndex: number): FreshCoin {
+  let priv = new EddsaPrivateKey();
+  priv.isWeak = true;
+  let blindingKey = new RsaBlindingKeySecret();
+  blindingKey.isWeak = true;
+  let buf = new ByteArray(priv.size() + blindingKey.size());
+
+  emsc.setup_fresh_coin(secretSeed.nativePtr, coinIndex, buf.nativePtr);
+
+  priv.nativePtr = buf.nativePtr;
+  blindingKey.nativePtr = buf.nativePtr + priv.size();
+
+  return {priv, blindingKey};
+}