feat: create receiver wallet for easier support sending to counterpar…

…ty's segwit addresses
zkfriendly · Apr 26, 2024 · f4b8047 · f4b8047
1 parent 0a2f02c
commit f4b8047
Show file tree

Hide file tree

Showing 4 changed files with 52 additions and 0 deletions.
diff --git a/src/bip47.js b/src/bip47.js
@@ -32,6 +32,23 @@ function BIP47Factory(ecc) {
             const prvKey = uintArrayToBuffer(prvKeyUint8);
             return bip32.fromPrivateKey(prvKey, bobNode.chainCode, this.network.network);
         }
+        getReceiveWallet(bobNode, index) {
+            if (!this.network || !this.RootPaymentCodeNode)
+                throw new Error('Root Payment code node or network not set');
+            const aliceNode = this.RootPaymentCodeNode.derive(0);
+            bobNode = bobNode.derive(index);
+            if (aliceNode.privateKey === undefined)
+                throw new Error('Missing private key to generate receive wallets');
+            const s = getSharedSecret(bobNode.publicKey, aliceNode.privateKey);
+            const sG = ecc.pointMultiply(G, s, true);
+            if (sG === null)
+                throw new Error('Could not calculate private key');
+            const pubKeyUint8 = ecc.pointAdd(bobNode.publicKey, sG);
+            if (pubKeyUint8 === null)
+                throw new Error('Could not sum pub keys');
+            const pubKey = uintArrayToBuffer(pubKeyUint8);
+            return bip32.fromPublicKey(pubKey, bobNode.chainCode, this.network.network);
+        }
         getPaymentCodeNode() {
             return this.RootPaymentCodeNode;
         }

diff --git a/ts-src/bip47.ts b/ts-src/bip47.ts
@@ -71,6 +71,35 @@ export function BIP47Factory(ecc: TinySecp256k1Interface): BIP47API {
       );
     }
 
+    getReceiveWallet(bobNode: BIP32Interface, index: number): BIP32Interface {
+      if (!this.network || !this.RootPaymentCodeNode)
+        throw new Error('Root Payment code node or network not set');
+
+      const aliceNode = this.RootPaymentCodeNode.derive(0);
+
+      bobNode = bobNode.derive(index);
+
+      if (aliceNode.privateKey === undefined)
+        throw new Error('Missing private key to generate receive wallets');
+
+      const s = getSharedSecret(bobNode.publicKey, aliceNode.privateKey);
+
+      const sG = ecc.pointMultiply(G, s, true);
+
+      if (sG === null) throw new Error('Could not calculate private key');
+
+      const pubKeyUint8 = ecc.pointAdd(bobNode.publicKey, sG);
+
+      if (pubKeyUint8 === null) throw new Error('Could not sum pub keys');
+
+      const pubKey = uintArrayToBuffer(pubKeyUint8);
+      return bip32.fromPublicKey(
+        pubKey,
+        bobNode.chainCode,
+        this.network.network,
+      );
+    }
+
     getPaymentCodeNode(): BIP32Interface {
       return this.RootPaymentCodeNode as BIP32Interface;
     }

diff --git a/ts-src/interfaces.ts b/ts-src/interfaces.ts
@@ -41,6 +41,11 @@ export interface BIP47Interface {
     index: number,
   ): BIP32Interface;
 
+  getReceiveWallet(
+    bobsRootPaymentCodeNode: BIP32Interface,
+    index: number,
+  ): BIP32Interface;
+
   getPaymentCodeNode(): BIP32Interface;
 
   getPaymentAddress(

diff --git a/types/interfaces.d.ts b/types/interfaces.d.ts
@@ -20,6 +20,7 @@ export interface BIP47Interface {
     network: NetworkCoin;
     RootPaymentCodeNode: BIP32Interface;
     getPaymentWallet(bobsRootPaymentCodeNode: BIP32Interface, index: number): BIP32Interface;
+    getReceiveWallet(bobsRootPaymentCodeNode: BIP32Interface, index: number): BIP32Interface;
     getPaymentCodeNode(): BIP32Interface;
     getPaymentAddress(bobsRootPaymentCodeNode: BIP32Interface, index: number): string;
     getSerializedPaymentCode(): string;