diff --git a/src/org/thoughtcrime/securesms/backup/FullBackupExporter.java b/src/org/thoughtcrime/securesms/backup/FullBackupExporter.java
index a5e90a1960..20f0a32e05 100644
--- a/src/org/thoughtcrime/securesms/backup/FullBackupExporter.java
+++ b/src/org/thoughtcrime/securesms/backup/FullBackupExporter.java
@@ -256,6 +256,7 @@ public class FullBackupExporter extends FullBackupBase {
       try {
         Conversions.intToByteArray(iv, 0, counter++);
         cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(cipherKey, "AES"), new IvParameterSpec(iv));
+        mac.update(iv);
 
         byte[] buffer = new byte[8192];
         int read;
diff --git a/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java b/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
index d5c914e209..1620b26158 100644
--- a/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
+++ b/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
@@ -171,6 +171,7 @@ public class FullBackupImporter extends FullBackupBase {
       try {
         Conversions.intToByteArray(iv, 0, counter++);
         cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(cipherKey, "AES"), new IvParameterSpec(iv));
+        mac.update(iv);
 
         byte[] buffer = new byte[8192];