partial implementation of tipping

2 files changed, 36 insertions, 0 deletions

diff --git a/src/crypto/cryptoApi.ts b/src/crypto/cryptoApi.ts
index 00013f0d3..5300c1370 100644
--- a/src/crypto/cryptoApi.ts
+++ b/src/crypto/cryptoApi.ts
@@ -34,6 +34,7 @@ import {
   PreCoinRecord,
   RefreshSessionRecord,
   ReserveRecord,
+  TipPlanchet,
   WireFee,
 } from "../types";
 
@@ -253,6 +254,10 @@ export class CryptoApi {
     return this.doRpc<PreCoinRecord>("createPreCoin", 1, denom, reserve);
   }
 
+  createTipPlanchet(denom: DenominationRecord): Promise<TipPlanchet> {
+    return this.doRpc<TipPlanchet>("createTipPlanchet", 1, denom);
+  }
+
   hashString(str: string): Promise<string> {
     return this.doRpc<string>("hashString", 1, str);
   }
diff --git a/src/crypto/cryptoWorker.ts b/src/crypto/cryptoWorker.ts
index 0a93fcb07..5ec7c18e5 100644
--- a/src/crypto/cryptoWorker.ts
+++ b/src/crypto/cryptoWorker.ts
@@ -40,6 +40,7 @@ import {
   RefreshPreCoinRecord,
   RefreshSessionRecord,
   ReserveRecord,
+  TipPlanchet,
   WireFee,
 } from "../types";
 
@@ -103,6 +104,7 @@ namespace RpcFunctions {
       coinValue: denom.value,
       denomPub: denomPub.encode().toCrock(),
       exchangeBaseUrl: reserve.exchange_base_url,
+      isFromTip: false,
       reservePub: reservePub.toCrock(),
       withdrawSig: sig.toCrock(),
     };
@@ -110,6 +112,35 @@ namespace RpcFunctions {
   }
 
 
+  export function createTipPlanchet(denom: DenominationRecord): TipPlanchet {
+    const denomPub = native.RsaPublicKey.fromCrock(denom.denomPub);
+    const coinPriv = native.EddsaPrivateKey.create();
+    const coinPub = coinPriv.getPublicKey();
+    const blindingFactor = native.RsaBlindingKeySecret.create();
+    const pubHash: native.HashCode = coinPub.hash();
+    const ev = native.rsaBlind(pubHash, blindingFactor, denomPub);
+
+    if (!ev) {
+      throw Error("couldn't blind (malicious exchange key?)");
+    }
+
+    if (!denom.feeWithdraw) {
+      throw Error("Field fee_withdraw missing");
+    }
+
+    const tipPlanchet: TipPlanchet = {
+      blindingKey: blindingFactor.toCrock(),
+      coinEv: ev.toCrock(),
+      coinPriv: coinPriv.toCrock(),
+      coinPub: coinPub.toCrock(),
+      coinValue: denom.value,
+      denomPubHash: denomPub.encode().hash().toCrock(),
+      denomPub: denomPub.encode().toCrock(),
+    };
+    return tipPlanchet;
+  }
+
+
   /**
    * Create and sign a message to request payback for a coin.
    */