From a77f7823186bdcead912e78d7f593b7578414e90 Mon Sep 17 00:00:00 2001
From: Emil Lundberg <emil@yubico.com>
Date: Thu, 29 Aug 2024 16:04:02 +0200
Subject: [PATCH] Fix HMAC in arkgHmacKem

See: https://github.com/Yubico/arkg-rfc/pull/21
---
 src/arkg/index.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/arkg/index.ts b/src/arkg/index.ts
index cfe8fa79b..e08367ee6 100644
--- a/src/arkg/index.ts
+++ b/src/arkg/index.ts
@@ -175,7 +175,7 @@ function arkgHmacKem<PublicKey, PrivateKey>(
 				false,
 				["sign"],
 			);
-			const t = toU8(await crypto.subtle.sign("HMAC", mk, info_sub)).slice(0, 16);
+			const t = toU8(await crypto.subtle.sign("HMAC", mk, c_prime)).slice(0, 16);
 
 			const k = await crypto.subtle.deriveBits(
 				{
@@ -214,7 +214,7 @@ function arkgHmacKem<PublicKey, PrivateKey>(
 				["sign"],
 			);
 
-			const t_prime = new Uint8Array(await crypto.subtle.sign("HMAC", mk, info_sub)).slice(0, 16);
+			const t_prime = new Uint8Array(await crypto.subtle.sign("HMAC", mk, c_prime)).slice(0, 16);
 			if (byteArrayEquals(t, t_prime)) {
 				const k = await crypto.subtle.deriveBits(
 					{