taler-typescript-core

commit c085f242e6062070e7a6a5413e71e94ed49bea3c
parent acd8d1da4cdfa4d6036a4ec9928962dd2417bc50
Author: Florian Dold <florian@dold.me>
Date:   Fri, 25 Apr 2025 16:32:30 +0200

util: fix planchet derivation for refreshV2

Diffstat:
M
packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
 | 
58
+++++++++++++++++++++++++++++++++++++++++++++++++++++-----

1 file changed, 53 insertions(+), 5 deletions(-)
diff --git a/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts b/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
@@ -233,6 +233,10 @@ export interface TalerCryptoInterface {
     req: SetupRefreshPlanchetRequest,
   ): Promise<FreshCoinEncoded>;
 
+  setupRefreshPlanchetV2(
+    req: SetupRefreshPlanchetRequestV2,
+  ): Promise<FreshCoinEncoded>;
+
   setupWithdrawalPlanchet(
     req: SetupWithdrawalPlanchetRequest,
   ): Promise<FreshCoinEncoded>;
@@ -428,6 +432,11 @@ export const nullCrypto: TalerCryptoInterface = {
   ): Promise<FreshCoinEncoded> {
     throw new Error("Function not implemented.");
   },
+  setupRefreshPlanchetV2: function (
+    req: SetupRefreshPlanchetRequestV2,
+  ): Promise<FreshCoinEncoded> {
+    throw new Error("Function not implemented.");
+  },
   rsaBlind: function (req: RsaBlindRequest): Promise<RsaBlindResponse> {
     throw new Error("Function not implemented.");
   },
@@ -557,6 +566,15 @@ export interface SetupRefreshPlanchetRequest {
   coinNumber: number;
 }
 
+export interface SetupRefreshPlanchetRequestV2 {
+  /**
+   * Refresh planchet secret, derived from the
+   * secret signature made by the old coin.
+   */
+  refreshPlanchetSecret: string;
+  coinNumber: number;
+}
+
 export interface SetupWithdrawalPlanchetRequest {
   secretSeed: string;
   coinNumber: number;
@@ -840,6 +858,36 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
     };
   },
 
+  async setupRefreshPlanchetV2(
+    tci: TalerCryptoInterfaceR,
+    req: SetupRefreshPlanchetRequestV2,
+  ): Promise<FreshCoinEncoded> {
+    const planchetMasterSecret = decodeCrock(req.refreshPlanchetSecret);
+
+    const coinPriv = kdfKw({
+      ikm: planchetMasterSecret,
+      outputLength: 32,
+      salt: stringToBytes("coin"),
+    });
+
+    const bks = kdfKw({
+      ikm: planchetMasterSecret,
+      outputLength: 32,
+      salt: stringToBytes("bks"),
+    });
+
+    const coinPrivEnc = encodeCrock(coinPriv);
+    const coinPubRes = await tci.eddsaGetPublic(tci, {
+      priv: coinPrivEnc,
+    });
+
+    return {
+      bks: encodeCrock(bks),
+      coinPriv: coinPrivEnc,
+      coinPub: coinPubRes.pub,
+    };
+  },
+
   async setupWithdrawalPlanchet(
     tci: TalerCryptoInterfaceR,
     req: SetupWithdrawalPlanchetRequest,
@@ -1539,7 +1587,7 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
       });
       signatures.push(sig.sig);
 
-      const planchetSecretBytes = kdfKw({
+      const planchetSecretsBytes = kdfKw({
         outputLength: 32 * numCoins,
         salt: stringToBytes("refresh-planchet-secret"),
         ikm: decodeCrock(sig.sig),
@@ -1549,20 +1597,20 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
         const denomSel = newCoinDenoms[j];
         for (let k = 0; k < newCoinDenoms[j].count; k++) {
           const coinIndex = planchets.length;
-          const mySecret = planchetSecretBytes.slice(
+          const myPlanchetSecret = planchetSecretsBytes.slice(
             32 * coinIndex,
             32 * coinIndex + 32,
           );
-          let fresh: FreshCoinEncoded = await tci.setupRefreshPlanchet(tci, {
+          let fresh: FreshCoinEncoded = await tci.setupRefreshPlanchetV2(tci, {
             coinNumber: coinIndex,
-            transferSecret: encodeCrock(mySecret),
+            refreshPlanchetSecret: encodeCrock(myPlanchetSecret),
           });
           let newAc: AgeCommitmentProof | undefined = undefined;
           let newAch: HashCodeString | undefined = undefined;
           if (req.meltCoinAgeCommitmentProof) {
             newAc = await AgeRestriction.commitmentDerive(
               req.meltCoinAgeCommitmentProof,
-              mySecret,
+              myPlanchetSecret,
             );
             newAch = AgeRestriction.hashCommitment(newAc.commitment);
           }