From 4680b06d4715b1b62d903f45490d325506a1e959 Mon Sep 17 00:00:00 2001
From: greg <gregfromstl@gmail.com>
Date: Sun, 1 Dec 2024 14:57:30 +0000
Subject: [PATCH] feat: favor `v` in `Signature.toHex` (#35)

* BREAKING CHANGE: Use v when converting signatures to hex format

* changeset

* Update blue-flowers-applaud.md

---------

Co-authored-by: jxom <7336481+jxom@users.noreply.github.com>
---
 .changeset/blue-flowers-applaud.md | 5 +++++
 src/core/Signature.ts              | 2 +-
 src/core/_test/Signature.test.ts   | 6 +++---
 3 files changed, 9 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/blue-flowers-applaud.md

diff --git a/.changeset/blue-flowers-applaud.md b/.changeset/blue-flowers-applaud.md
new file mode 100644
index 00000000..5ee17e4e
--- /dev/null
+++ b/.changeset/blue-flowers-applaud.md
@@ -0,0 +1,5 @@
+---
+"ox": minor
+---
+
+Updated `Signature.toHex` to serialize the last byte as `v` instead of `yParity` for widened compatibility.
diff --git a/src/core/Signature.ts b/src/core/Signature.ts
index 40f4113b..3995b295 100644
--- a/src/core/Signature.ts
+++ b/src/core/Signature.ts
@@ -527,7 +527,7 @@ export function toHex(signature: Signature<boolean>): Hex.Hex {
     Hex.fromNumber(s, { size: 32 }),
     // If the signature is recovered, add the recovery byte to the signature.
     typeof signature.yParity === 'number'
-      ? Hex.fromNumber(signature.yParity, { size: 1 })
+      ? Hex.fromNumber(yParityToV(signature.yParity), { size: 1 })
       : '0x',
   )
 
diff --git a/src/core/_test/Signature.test.ts b/src/core/_test/Signature.test.ts
index 38a3b222..60b4ccb0 100644
--- a/src/core/_test/Signature.test.ts
+++ b/src/core/_test/Signature.test.ts
@@ -444,7 +444,7 @@ describe('serialize', () => {
         yParity: 1,
       }),
     ).toMatchInlineSnapshot(
-      `"0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db801"`,
+      `"0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db81c"`,
     )
 
     expect(
@@ -454,7 +454,7 @@ describe('serialize', () => {
         yParity: 0,
       }),
     ).toMatchInlineSnapshot(
-      `"0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db800"`,
+      `"0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db81b"`,
     )
 
     expect(
@@ -543,7 +543,7 @@ describe('toBytes', () => {
       215,
       109,
       184,
-      1,
+      28,
     ]
   `,
     )