From 18302b3357ade3d216019ba12721269a9362cf89 Mon Sep 17 00:00:00 2001
From: overtorment <overtorment@gmail.com>
Date: Thu, 30 May 2024 11:35:35 +0100
Subject: [PATCH] fix: return actuall addresses in outputs instead of pubkeys

---
 package.json                 |  2 +-
 src/index.ts                 | 11 ++++++++++-
 tests/silent-payment.test.ts | 14 +++++++++++++-
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/package.json b/package.json
index 2ceae76..71c6c6a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "silent-payments",
-  "version": "0.3.3",
+  "version": "0.3.4",
   "description": "BIP-352",
   "main": "src/index.ts",
   "scripts": {
diff --git a/src/index.ts b/src/index.ts
index c02e830..50e0793 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -94,7 +94,7 @@ export class SilentPayment {
         const Pmk = Buffer.from(ecc.pointAdd(ecc.pointMultiply(G, tk) as Uint8Array, Bm) as Uint8Array);
 
         // Encode Pmk as a BIP341 taproot output
-        const address = Pmk.slice(1).toString("hex");
+        const address = SilentPayment.pubkeyToAddress(Pmk.slice(1).toString("hex"));
         const newTarget: Target = { address };
         newTarget.value = amount;
         ret.push(newTarget);
@@ -194,4 +194,13 @@ export class SilentPayment {
 
     return true;
   }
+
+  static pubkeyToAddress(hex: string): string {
+    const publicKey = Buffer.from("5120" + hex, "hex");
+    return bitcoin.address.fromOutputScript(publicKey, bitcoin.networks.bitcoin);
+  }
+
+  static addressToPubkey(address: string): string {
+    return bitcoin.address.toOutputScript(address).subarray(2).toString("hex");
+  }
 }
diff --git a/tests/silent-payment.test.ts b/tests/silent-payment.test.ts
index 57dd5ff..27a0336 100644
--- a/tests/silent-payment.test.ts
+++ b/tests/silent-payment.test.ts
@@ -69,7 +69,7 @@ tests.forEach((testCase, index) => {
         }).toThrow("No eligible UTXOs with private keys found");
       } else {
         const generated = sp.createTransaction(utxos, recipients);
-        const generated_pubkeys: string[] = generated.map((obj) => obj.address).filter(Boolean) as string[];
+        const generated_pubkeys: string[] = generated.map((obj) => SilentPayment.addressToPubkey(String(obj.address))).filter(Boolean) as string[];
         assert(matchSubset(generated_pubkeys, sending.expected.outputs));
       }
     });
@@ -176,3 +176,15 @@ it("can validate payment code", () => {
   assert.ok(!SilentPayment.isPaymentCodeValid("qqgste7k9hx0qftg6qmwlkqtwuy6cycyavzmzj85c6qdfhjdpdjtdgqjuexzk6murw56suy3e0rd2cgqvycxttddwsvgxe2usfpxumr70xc9pkqwv")); // no prefix
   assert.ok(!SilentPayment.isPaymentCodeValid("qqgste7k9hx0qftg6qmwlkqtwuy6cycyavzmzj85c6qdfhjdpdjtdgqjuexzk6murw56suy3e0rd2cgqvycxttddwsvgxe2usfpxumr70xc9pkqwv123")); // no prefix
 });
+
+it("can turn pubkey into taproot address", () => {
+  assert.strictEqual(SilentPayment.pubkeyToAddress("40ef293a8a0ebaf8b351a27d89ff4b5b3822a635e4afdca77a30170c363bafa3"), "bc1pgrhjjw52p6a03v635f7cnl6ttvuz9f34ujhaefm6xqtscd3m473szkl92g");
+
+  expect(() => {
+    SilentPayment.pubkeyToAddress("512040ef293a8a0ebaf8b351a27d89ff4b5b3822a635e4afdca77a30170c363bafa3");
+  }).toThrow(/has no matching Address/);
+});
+
+it("can turn taproot address into pubkey", () => {
+  assert.strictEqual(SilentPayment.addressToPubkey("bc1pgrhjjw52p6a03v635f7cnl6ttvuz9f34ujhaefm6xqtscd3m473szkl92g"), "40ef293a8a0ebaf8b351a27d89ff4b5b3822a635e4afdca77a30170c363bafa3");
+});