From de584ccb7dfa519851de179ffa9398d1091e4088 Mon Sep 17 00:00:00 2001
From: Greyson Parrelli <greyson@signal.org>
Date: Thu, 9 Apr 2026 22:10:20 -0400
Subject: [PATCH] Use message digest for faster comparison.

---
 .../java/org/signal/archive/stream/EncryptedBackupReader.kt    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/archive/src/main/java/org/signal/archive/stream/EncryptedBackupReader.kt b/lib/archive/src/main/java/org/signal/archive/stream/EncryptedBackupReader.kt
index 914dce2d8a..06c9c8440a 100644
--- a/lib/archive/src/main/java/org/signal/archive/stream/EncryptedBackupReader.kt
+++ b/lib/archive/src/main/java/org/signal/archive/stream/EncryptedBackupReader.kt
@@ -23,6 +23,7 @@ import java.io.ByteArrayOutputStream
 import java.io.EOFException
 import java.io.IOException
 import java.io.InputStream
+import java.security.MessageDigest
 import java.util.zip.GZIPInputStream
 import javax.crypto.Cipher
 import javax.crypto.CipherInputStream
@@ -145,7 +146,7 @@ class EncryptedBackupReader private constructor(
       val calculatedMac = macStream.mac.doFinal()
       val expectedMac = dataStream.readNBytesOrThrow(MAC_SIZE)
 
-      if (!calculatedMac.contentEquals(expectedMac)) {
+      if (!MessageDigest.isEqual(calculatedMac, expectedMac)) {
         throw IOException("Invalid MAC!")
       }
     }