From e63ebe159436af951ad8bfa0db779717e1194683 Mon Sep 17 00:00:00 2001
From: M66B <M66B@users.noreply.github.com>
Date: Fri, 16 May 2025 08:09:05 +0200
Subject: [PATCH] Ensure cloud sync IV is 12 bytes

---
 app/src/main/java/eu/faircode/email/CloudSync.java | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/eu/faircode/email/CloudSync.java b/app/src/main/java/eu/faircode/email/CloudSync.java
index 371a4a3c75..9866207a10 100644
--- a/app/src/main/java/eu/faircode/email/CloudSync.java
+++ b/app/src/main/java/eu/faircode/email/CloudSync.java
@@ -777,7 +777,8 @@ public class CloudSync {
 
     private static byte[] getIv(long revision) {
         byte[] iv = ByteBuffer.allocate(12)
-                .putLong(revision)
+                .putLong(revision) // 8 bytes
+                .putInt(0) // 4 bytes
                 .array();
         return iv;
     }
@@ -785,7 +786,7 @@ public class CloudSync {
     private static byte[] getAd(String key, long revision) throws NoSuchAlgorithmException {
         byte[] k = MessageDigest.getInstance("SHA256").digest(key.getBytes());
         byte[] ad = ByteBuffer.allocate(8 + 8)
-                .putLong(revision)
+                .putLong(revision) // 8 bytes
                 .put(Arrays.copyOfRange(k, 0, 8))
                 .array();
         return ad;