derive tipping planchets from seed, implement backup further

3 files changed, 34 insertions, 28 deletions

diff --git a/packages/taler-wallet-core/src/crypto/talerCrypto.ts b/packages/taler-wallet-core/src/crypto/talerCrypto.ts
index 4faa523a0..095957982 100644
--- a/packages/taler-wallet-core/src/crypto/talerCrypto.ts
+++ b/packages/taler-wallet-core/src/crypto/talerCrypto.ts
@@ -390,6 +390,25 @@ export function setupRefreshPlanchet(
   };
 }
 
+export function setupTipPlanchet(
+  secretSeed: Uint8Array,
+  coinNumber: number,
+): FreshCoin {
+  const info = stringToBytes("taler-tip-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),
+  };
+}
+
 export function setupRefreshTransferPub(
   secretSeed: Uint8Array,
   transferPubIndex: number,
diff --git a/packages/taler-wallet-core/src/crypto/workers/cryptoApi.ts b/packages/taler-wallet-core/src/crypto/workers/cryptoApi.ts
index 6a4264d2c..ef149823c 100644
--- a/packages/taler-wallet-core/src/crypto/workers/cryptoApi.ts
+++ b/packages/taler-wallet-core/src/crypto/workers/cryptoApi.ts
@@ -22,16 +22,7 @@
 /**
  * Imports.
  */
-import { AmountJson } from "../../util/amounts";
-
-import {
-  CoinRecord,
-  DenominationRecord,
-  RefreshSessionRecord,
-  TipPlanchet,
-  WireFee,
-  DenominationSelectionInfo,
-} from "../../types/dbTypes";
+import { CoinRecord, DenominationRecord, WireFee } from "../../types/dbTypes";
 
 import { CryptoWorker } from "./cryptoWorker";
 
@@ -49,7 +40,9 @@ import * as timer from "../../util/timer";
 import { Logger } from "../../util/logging";
 import {
   DerivedRefreshSession,
+  DerivedTipPlanchet,
   DeriveRefreshSessionRequest,
+  DeriveTipRequest,
 } from "../../types/cryptoTypes";
 
 const logger = new Logger("cryptoApi.ts");
@@ -329,8 +322,8 @@ export class CryptoApi {
     return this.doRpc<PlanchetCreationResult>("createPlanchet", 1, req);
   }
 
-  createTipPlanchet(denom: DenominationRecord): Promise<TipPlanchet> {
-    return this.doRpc<TipPlanchet>("createTipPlanchet", 1, denom);
+  createTipPlanchet(req: DeriveTipRequest): Promise<DerivedTipPlanchet> {
+    return this.doRpc<DerivedTipPlanchet>("createTipPlanchet", 1, req);
   }
 
   hashString(str: string): Promise<string> {
diff --git a/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts b/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
index d14f663e8..deaad42bb 100644
--- a/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
+++ b/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
@@ -30,11 +30,8 @@ import {
   CoinRecord,
   DenominationRecord,
   RefreshPlanchet,
-  RefreshSessionRecord,
-  TipPlanchet,
   WireFee,
   CoinSourceType,
-  DenominationSelectionInfo,
 } from "../../types/dbTypes";
 
 import { CoinDepositPermission, RecoupRequest } from "../../types/talerTypes";
@@ -59,25 +56,25 @@ import {
   rsaUnblind,
   stringToBytes,
   createHashContext,
-  createEcdheKeyPair,
   keyExchangeEcdheEddsa,
   setupRefreshPlanchet,
   rsaVerify,
-  getRandomBytes,
   setupRefreshTransferPub,
+  setupTipPlanchet,
 } from "../talerCrypto";
 import { randomBytes } from "../primitives/nacl-fast";
 import { kdf } from "../primitives/kdf";
 import {
   Timestamp,
-  getTimestampNow,
   timestampTruncateToSecond,
 } from "../../util/time";
 
 import { Logger } from "../../util/logging";
 import {
   DerivedRefreshSession,
+  DerivedTipPlanchet,
   DeriveRefreshSessionRequest,
+  DeriveTipRequest,
 } from "../../types/cryptoTypes";
 
 const logger = new Logger("cryptoImplementation.ts");
@@ -199,21 +196,18 @@ export class CryptoImplementation {
   /**
    * Create a planchet used for tipping, including the private keys.
    */
-  createTipPlanchet(denom: DenominationRecord): TipPlanchet {
-    const denomPub = decodeCrock(denom.denomPub);
-    const coinKeyPair = createEddsaKeyPair();
+  createTipPlanchet(req: DeriveTipRequest): DerivedTipPlanchet {
+    const fc = setupTipPlanchet(decodeCrock(req.secretSeed), req.planchetIndex);
+    const denomPub = decodeCrock(req.denomPub);
     const blindingFactor = createBlindingKeySecret();
-    const coinPubHash = hash(coinKeyPair.eddsaPub);
+    const coinPubHash = hash(fc.coinPub);
     const ev = rsaBlind(coinPubHash, blindingFactor, denomPub);
 
-    const tipPlanchet: TipPlanchet = {
+    const tipPlanchet: DerivedTipPlanchet = {
       blindingKey: encodeCrock(blindingFactor),
       coinEv: encodeCrock(ev),
-      coinPriv: encodeCrock(coinKeyPair.eddsaPriv),
-      coinPub: encodeCrock(coinKeyPair.eddsaPub),
-      coinValue: denom.value,
-      denomPub: encodeCrock(denomPub),
-      denomPubHash: encodeCrock(hash(denomPub)),
+      coinPriv: encodeCrock(fc.coinPriv),
+      coinPub: encodeCrock(fc.coinPub),
     };
     return tipPlanchet;
   }