1 files changed, 27 insertions, 0 deletions
diff --git a/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts b/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
index 52d2dd24e..fa1271a7b 100644
--- a/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
+++ b/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
@@ -33,6 +33,7 @@ import {
   AmountString,
   BlindedDenominationSignature,
   bufferForUint32,
+  bufferForUint64,
   buildSigPS,
   CoinDepositPermission,
   CoinEnvelope,
@@ -105,6 +106,8 @@ import {
   EncryptedContract,
   SignPurseMergeRequest,
   SignPurseMergeResponse,
+  SignRefundRequest,
+  SignRefundResponse,
   SignReservePurseCreateRequest,
   SignReservePurseCreateResponse,
   SignTrackTransactionRequest,
@@ -233,6 +236,8 @@ export interface TalerCryptoInterface {
   signReservePurseCreate(
     req: SignReservePurseCreateRequest,
   ): Promise<SignReservePurseCreateResponse>;
+
+  signRefund(req: SignRefundRequest): Promise<SignRefundResponse>;
 }
 
 /**
@@ -409,6 +414,9 @@ export const nullCrypto: TalerCryptoInterface = {
   ): Promise<SignReservePurseCreateResponse> {
     throw new Error("Function not implemented.");
   },
+  signRefund: function (req: SignRefundRequest): Promise<SignRefundResponse> {
+    throw new Error("Function not implemented.");
+  },
 };
 
 export type WithArg<X> = X extends (req: infer T) => infer R
@@ -928,6 +936,7 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
     const pub = decodeCrock(masterPub);
     return { valid: eddsaVerify(p, sig, pub) };
   },
+
   /**
    * Check if the signature of a denomination is valid.
    */
@@ -1625,6 +1634,24 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
       purseSig: purseSigResp.sig,
     };
   },
+  async signRefund(
+    tci: TalerCryptoInterfaceR,
+    req: SignRefundRequest,
+  ): Promise<SignRefundResponse> {
+    const refundSigBlob = buildSigPS(TalerSignaturePurpose.MERCHANT_REFUND)
+      .put(decodeCrock(req.contractTermsHash))
+      .put(decodeCrock(req.coinPub))
+      .put(bufferForUint64(req.rtransactionId))
+      .put(amountToBuffer(req.refundAmount))
+      .build();
+    const refundSigResp = await tci.eddsaSign(tci, {
+      msg: encodeCrock(refundSigBlob),
+      priv: req.merchantPriv,
+    });
+    return {
+      sig: refundSigResp.sig,
+    };
+  },
 };
 
 function amountToBuffer(amount: AmountLike): Uint8Array {