From 547f65025b594206457171c6739fe9b39220cd7e Mon Sep 17 00:00:00 2001
From: Chris Anderson <jchris@gmail.com>
Date: Tue, 13 Aug 2024 15:07:31 -0700
Subject: [PATCH] move to 96 bits

---
 src/runtime/keyed-crypto.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/runtime/keyed-crypto.ts b/src/runtime/keyed-crypto.ts
index 93b47e99..fdd32a06 100644
--- a/src/runtime/keyed-crypto.ts
+++ b/src/runtime/keyed-crypto.ts
@@ -83,8 +83,11 @@ export class BlockIvKeyIdCodec implements BlockCodec<0x300539, Uint8Array> {
     let hashArray;
     if (!this.iv) {
       const hash = await hasher.digest(data);
-      const doubleHash = await hasher.digest(hash.bytes);
-      hashArray = new Uint8Array(doubleHash.bytes);
+      const hashBytes = new Uint8Array(hash.bytes);
+      hashArray = new Uint8Array(12); // 96 bits = 12 bytes
+      for (let i = 0; i < hashBytes.length; i++) {
+        hashArray[i % 12] ^= hashBytes[i];
+      }
     }
     const { iv } = this.ko.algo(this.iv || hashArray);
     const fprt = await this.ko.fingerPrint();