peer-to-peer pull payments MVP

p2p pull wip

4 files changed, 240 insertions, 29 deletions

diff --git a/packages/taler-util/src/talerCrypto.ts b/packages/taler-util/src/talerCrypto.ts
index 38bb5ad0a..d7734707a 100644
--- a/packages/taler-util/src/talerCrypto.ts
+++ b/packages/taler-util/src/talerCrypto.ts
@@ -1214,6 +1214,9 @@ type ContractPrivateKey = FlavorP<Uint8Array, "ContractPrivateKey", 32> &
 type MergePrivateKey = FlavorP<Uint8Array, "MergePrivateKey", 32> &
   MaterialEddsaPriv;
 
+const mergeSalt = "p2p-merge-contract";
+const depositSalt = "p2p-deposit-contract";
+
 export function encryptContractForMerge(
   pursePub: PursePublicKey,
   contractPriv: ContractPrivateKey,
@@ -1230,12 +1233,24 @@ export function encryptContractForMerge(
     contractTermsCompressed,
   ]);
   const key = keyExchangeEcdheEddsa(contractPriv, pursePub);
-  return encryptWithDerivedKey(
-    getRandomBytesF(24),
-    key,
-    data,
-    "p2p-merge-contract",
-  );
+  return encryptWithDerivedKey(getRandomBytesF(24), key, data, mergeSalt);
+}
+
+export function encryptContractForDeposit(
+  pursePub: PursePublicKey,
+  contractPriv: ContractPrivateKey,
+  contractTerms: any,
+): Promise<OpaqueData> {
+  const contractTermsCanon = canonicalJson(contractTerms) + "\0";
+  const contractTermsBytes = stringToBytes(contractTermsCanon);
+  const contractTermsCompressed = fflate.zlibSync(contractTermsBytes);
+  const data = typedArrayConcat([
+    bufferForUint32(ContractFormatTag.PaymentRequest),
+    bufferForUint32(contractTermsBytes.length),
+    contractTermsCompressed,
+  ]);
+  const key = keyExchangeEcdheEddsa(contractPriv, pursePub);
+  return encryptWithDerivedKey(getRandomBytesF(24), key, data, depositSalt);
 }
 
 export interface DecryptForMergeResult {
@@ -1243,13 +1258,17 @@ export interface DecryptForMergeResult {
   mergePriv: Uint8Array;
 }
 
+export interface DecryptForDepositResult {
+  contractTerms: any;
+}
+
 export async function decryptContractForMerge(
   enc: OpaqueData,
   pursePub: PursePublicKey,
   contractPriv: ContractPrivateKey,
 ): Promise<DecryptForMergeResult> {
   const key = keyExchangeEcdheEddsa(contractPriv, pursePub);
-  const dec = await decryptWithDerivedKey(enc, key, "p2p-merge-contract");
+  const dec = await decryptWithDerivedKey(enc, key, mergeSalt);
   const mergePriv = dec.slice(8, 8 + 32);
   const contractTermsCompressed = dec.slice(8 + 32);
   const contractTermsBuf = fflate.unzlibSync(contractTermsCompressed);
@@ -1263,6 +1282,20 @@ export async function decryptContractForMerge(
   };
 }
 
-export function encryptContractForDeposit() {
-  throw Error("not implemented");
+export async function decryptContractForDeposit(
+  enc: OpaqueData,
+  pursePub: PursePublicKey,
+  contractPriv: ContractPrivateKey,
+): Promise<DecryptForDepositResult> {
+  const key = keyExchangeEcdheEddsa(contractPriv, pursePub);
+  const dec = await decryptWithDerivedKey(enc, key, depositSalt);
+  const contractTermsCompressed = dec.slice(8);
+  const contractTermsBuf = fflate.unzlibSync(contractTermsCompressed);
+  // Slice of the '\0' at the end and decode to a string
+  const contractTermsString = bytesToString(
+    contractTermsBuf.slice(0, contractTermsBuf.length - 1),
+  );
+  return {
+    contractTerms: JSON.parse(contractTermsString),
+  };
 }
diff --git a/packages/taler-util/src/talerTypes.ts b/packages/taler-util/src/talerTypes.ts
index d4de8c37b..ee2dee93c 100644
--- a/packages/taler-util/src/talerTypes.ts
+++ b/packages/taler-util/src/talerTypes.ts
@@ -1874,3 +1874,74 @@ export interface PeerContractTerms {
   summary: string;
   purse_expiration: TalerProtocolTimestamp;
 }
+
+export interface EncryptedContract {
+  // Encrypted contract.
+  econtract: string;
+
+  // Signature over the (encrypted) contract.
+  econtract_sig: string;
+
+  // Ephemeral public key for the DH operation to decrypt the encrypted contract.
+  contract_pub: string;
+}
+
+/**
+ * Payload for /reserves/{reserve_pub}/purse
+ * endpoint of the exchange.
+ */
+export interface ExchangeReservePurseRequest {
+  /**
+   * Minimum amount that must be credited to the reserve, that is
+   * the total value of the purse minus the deposit fees.
+   * If the deposit fees are lower, the contribution to the
+   * reserve can be higher!
+   */
+  purse_value: AmountString;
+
+  // Minimum age required for all coins deposited into the purse.
+  min_age: number;
+
+  // Purse fee the reserve owner is willing to pay
+  // for the purse creation. Optional, if not present
+  // the purse is to be created from the purse quota
+  // of the reserve.
+  purse_fee: AmountString;
+
+  // Optional encrypted contract, in case the buyer is
+  // proposing the contract and thus establishing the
+  // purse with the payment.
+  econtract?: EncryptedContract;
+
+  // EdDSA public key used to approve merges of this purse.
+  merge_pub: EddsaPublicKeyString;
+
+  // EdDSA signature of the purse private key affirming the merge
+  // over a TALER_PurseMergeSignaturePS.
+  // Must be of purpose TALER_SIGNATURE_PURSE_MERGE.
+  merge_sig: EddsaSignatureString;
+
+  // EdDSA signature of the account/reserve affirming the merge.
+  // Must be of purpose TALER_SIGNATURE_WALLET_ACCOUNT_MERGE
+  reserve_sig: EddsaSignatureString;
+
+  // Purse public key.
+  purse_pub: EddsaPublicKeyString;
+
+  // EdDSA signature of the purse over
+  // TALER_PurseRequestSignaturePS of
+  // purpose TALER_SIGNATURE_PURSE_REQUEST
+  // confirming that the
+  // above details hold for this purse.
+  purse_sig: EddsaSignatureString;
+
+  // SHA-512 hash of the contact of the purse.
+  h_contract_terms: HashCodeString;
+
+  // Client-side timestamp of when the merge request was made.
+  merge_timestamp: TalerProtocolTimestamp;
+
+  // Indicative time by which the purse should expire
+  // if it has not been paid.
+  purse_expiration: TalerProtocolTimestamp;
+}
diff --git a/packages/taler-util/src/taleruri.ts b/packages/taler-util/src/taleruri.ts
index e3bd120f0..e7d66d7d5 100644
--- a/packages/taler-util/src/taleruri.ts
+++ b/packages/taler-util/src/taleruri.ts
@@ -45,6 +45,11 @@ export interface PayPushUriResult {
   contractPriv: string;
 }
 
+export interface PayPullUriResult {
+  exchangeBaseUrl: string;
+  contractPriv: string;
+}
+
 /**
  * Parse a taler[+http]://withdraw URI.
  * Return undefined if not passed a valid URI.
@@ -84,10 +89,14 @@ export enum TalerUriType {
   TalerTip = "taler-tip",
   TalerRefund = "taler-refund",
   TalerNotifyReserve = "taler-notify-reserve",
-  TalerPayPush = "pay-push",
+  TalerPayPush = "taler-pay-push",
+  TalerPayPull = "taler-pay-pull",
   Unknown = "unknown",
 }
 
+const talerActionPayPull = "pay-pull";
+const talerActionPayPush = "pay-push";
+
 /**
  * Classify a taler:// URI.
  */
@@ -117,12 +126,18 @@ export function classifyTalerUri(s: string): TalerUriType {
   if (sl.startsWith("taler+http://withdraw/")) {
     return TalerUriType.TalerWithdraw;
   }
-  if (sl.startsWith("taler://pay-push/")) {
+  if (sl.startsWith(`taler://${talerActionPayPush}/`)) {
     return TalerUriType.TalerPayPush;
   }
-  if (sl.startsWith("taler+http://pay-push/")) {
+  if (sl.startsWith(`taler+http://${talerActionPayPush}/`)) {
     return TalerUriType.TalerPayPush;
   }
+  if (sl.startsWith(`taler://${talerActionPayPull}/`)) {
+    return TalerUriType.TalerPayPull;
+  }
+  if (sl.startsWith(`taler+http://${talerActionPayPull}/`)) {
+    return TalerUriType.TalerPayPull;
+  }
   if (sl.startsWith("taler://notify-reserve/")) {
     return TalerUriType.TalerNotifyReserve;
   }
@@ -189,7 +204,29 @@ export function parsePayUri(s: string): PayUriResult | undefined {
 }
 
 export function parsePayPushUri(s: string): PayPushUriResult | undefined {
-  const pi = parseProtoInfo(s, "pay-push");
+  const pi = parseProtoInfo(s, talerActionPayPush);
+  if (!pi) {
+    return undefined;
+  }
+  const c = pi?.rest.split("?");
+  const parts = c[0].split("/");
+  if (parts.length < 2) {
+    return undefined;
+  }
+  const host = parts[0].toLowerCase();
+  const contractPriv = parts[parts.length - 1];
+  const pathSegments = parts.slice(1, parts.length - 1);
+  const p = [host, ...pathSegments].join("/");
+  const exchangeBaseUrl = canonicalizeBaseUrl(`${pi.innerProto}://${p}/`);
+
+  return {
+    exchangeBaseUrl,
+    contractPriv,
+  };
+}
+
+export function parsePayPullUri(s: string): PayPullUriResult | undefined {
+  const pi = parseProtoInfo(s, talerActionPayPull);
   if (!pi) {
     return undefined;
   }
@@ -283,3 +320,24 @@ export function constructPayPushUri(args: {
   }
   return `${proto}://pay-push/${url.host}${url.pathname}${args.contractPriv}`;
 }
+
+export function constructPayPullUri(args: {
+  exchangeBaseUrl: string;
+  contractPriv: string;
+}): string {
+  const url = new URL(args.exchangeBaseUrl);
+  let proto: string;
+  if (url.protocol === "https:") {
+    proto = "taler";
+  } else if (url.protocol === "http:") {
+    proto = "taler+http";
+  } else {
+    throw Error(`Unsupported exchange URL protocol ${args.exchangeBaseUrl}`);
+  }
+  if (!url.pathname.endsWith("/")) {
+    throw Error(
+      `exchange base URL must end with a slash (got ${args.exchangeBaseUrl}instead)`,
+    );
+  }
+  return `${proto}://pay-pull/${url.host}${url.pathname}${args.contractPriv}`;
+}
diff --git a/packages/taler-util/src/walletTypes.ts b/packages/taler-util/src/walletTypes.ts
index 7b482c60e..3a415b221 100644
--- a/packages/taler-util/src/walletTypes.ts
+++ b/packages/taler-util/src/walletTypes.ts
@@ -627,7 +627,7 @@ export interface ExchangeAccount {
   master_sig: string;
 }
 
-export type WireFeeMap = { [wireMethod: string]: WireFee[] }
+export type WireFeeMap = { [wireMethod: string]: WireFee[] };
 export interface WireInfo {
   feesForType: WireFeeMap;
   accounts: ExchangeAccount[];
@@ -639,7 +639,6 @@ const codecForExchangeAccount = (): Codec<ExchangeAccount> =>
     .property("master_sig", codecForString())
     .build("codecForExchangeAccount");
 
-
 const codecForWireFee = (): Codec<WireFee> =>
   buildCodecForObject<WireFee>()
     .property("sig", codecForString())
@@ -658,19 +657,18 @@ const codecForWireInfo = (): Codec<WireInfo> =>
 
 const codecForDenominationInfo = (): Codec<DenominationInfo> =>
   buildCodecForObject<DenominationInfo>()
-    .property("denomPubHash", (codecForString()))
-    .property("value", (codecForAmountJson()))
-    .property("feeWithdraw", (codecForAmountJson()))
-    .property("feeDeposit", (codecForAmountJson()))
-    .property("feeRefresh", (codecForAmountJson()))
-    .property("feeRefund", (codecForAmountJson()))
-    .property("stampStart", (codecForTimestamp))
-    .property("stampExpireWithdraw", (codecForTimestamp))
-    .property("stampExpireLegal", (codecForTimestamp))
-    .property("stampExpireDeposit", (codecForTimestamp))
+    .property("denomPubHash", codecForString())
+    .property("value", codecForAmountJson())
+    .property("feeWithdraw", codecForAmountJson())
+    .property("feeDeposit", codecForAmountJson())
+    .property("feeRefresh", codecForAmountJson())
+    .property("feeRefund", codecForAmountJson())
+    .property("stampStart", codecForTimestamp)
+    .property("stampExpireWithdraw", codecForTimestamp)
+    .property("stampExpireLegal", codecForTimestamp)
+    .property("stampExpireDeposit", codecForTimestamp)
     .build("codecForDenominationInfo");
 
-
 export interface DenominationInfo {
   value: AmountJson;
   denomPubHash: string;
@@ -713,7 +711,6 @@ export interface DenominationInfo {
    * Data after which coins of this denomination can't be deposited anymore.
    */
   stampExpireDeposit: TalerProtocolTimestamp;
-
 }
 
 export interface ExchangeListItem {
@@ -726,7 +723,6 @@ export interface ExchangeListItem {
   denominations: DenominationInfo[];
 }
 
-
 const codecForAuditorDenomSig = (): Codec<AuditorDenomSig> =>
   buildCodecForObject<AuditorDenomSig>()
     .property("denom_pub_h", codecForString())
@@ -740,7 +736,6 @@ const codecForExchangeAuditor = (): Codec<ExchangeAuditor> =>
     .property("denomination_keys", codecForList(codecForAuditorDenomSig()))
     .build("codecForExchangeAuditor");
 
-
 const codecForExchangeTos = (): Codec<ExchangeTos> =>
   buildCodecForObject<ExchangeTos>()
     .property("acceptedVersion", codecOptional(codecForString()))
@@ -1452,18 +1447,34 @@ export interface CheckPeerPushPaymentRequest {
   talerUri: string;
 }
 
+export interface CheckPeerPullPaymentRequest {
+  talerUri: string;
+}
+
 export interface CheckPeerPushPaymentResponse {
   contractTerms: any;
   amount: AmountString;
   peerPushPaymentIncomingId: string;
 }
 
+export interface CheckPeerPullPaymentResponse {
+  contractTerms: any;
+  amount: AmountString;
+  peerPullPaymentIncomingId: string;
+}
+
 export const codecForCheckPeerPushPaymentRequest =
   (): Codec<CheckPeerPushPaymentRequest> =>
     buildCodecForObject<CheckPeerPushPaymentRequest>()
       .property("talerUri", codecForString())
       .build("CheckPeerPushPaymentRequest");
 
+export const codecForCheckPeerPullPaymentRequest =
+  (): Codec<CheckPeerPullPaymentRequest> =>
+    buildCodecForObject<CheckPeerPullPaymentRequest>()
+      .property("talerUri", codecForString())
+      .build("CheckPeerPullPaymentRequest");
+
 export interface AcceptPeerPushPaymentRequest {
   /**
    * Transparent identifier of the incoming peer push payment.
@@ -1476,3 +1487,41 @@ export const codecForAcceptPeerPushPaymentRequest =
     buildCodecForObject<AcceptPeerPushPaymentRequest>()
       .property("peerPushPaymentIncomingId", codecForString())
       .build("AcceptPeerPushPaymentRequest");
+
+export interface AcceptPeerPullPaymentRequest {
+  /**
+   * Transparent identifier of the incoming peer pull payment.
+   */
+  peerPullPaymentIncomingId: string;
+}
+
+export const codecForAcceptPeerPullPaymentRequest =
+  (): Codec<AcceptPeerPullPaymentRequest> =>
+    buildCodecForObject<AcceptPeerPullPaymentRequest>()
+      .property("peerPullPaymentIncomingId", codecForString())
+      .build("AcceptPeerPllPaymentRequest");
+
+export interface InitiatePeerPullPaymentRequest {
+  /**
+   * FIXME: Make this optional?
+   */
+  exchangeBaseUrl: string;
+  amount: AmountString;
+  partialContractTerms: any;
+}
+
+export const codecForInitiatePeerPullPaymentRequest =
+  (): Codec<InitiatePeerPullPaymentRequest> =>
+    buildCodecForObject<InitiatePeerPullPaymentRequest>()
+      .property("partialContractTerms", codecForAny())
+      .property("amount", codecForAmountString())
+      .property("exchangeBaseUrl", codecForAmountString())
+      .build("InitiatePeerPullPaymentRequest");
+
+export interface InitiatePeerPullPaymentResponse {
+  /**
+   * Taler URI for the other party to make the payment
+   * that was requested.
+   */
+  talerUri: string;
+}