diff --git a/components/net/sf/briar/transport/IvEncoder.java b/components/net/sf/briar/transport/IvEncoder.java
index 997db2007c79de3335582c4ac3e2113145e7e3c7..c922cadc81fe94b39e9a9c3d6d2c213bef3b33ad 100644
--- a/components/net/sf/briar/transport/IvEncoder.java
+++ b/components/net/sf/briar/transport/IvEncoder.java
@@ -13,7 +13,7 @@ class IvEncoder {
 	}
 
 	static void updateIv(byte[] iv, long frame) {
-		// Encode the frame number as a uint32, leaving 2 bytes for the counter
-		ByteUtils.writeUint32(frame, iv, iv.length - 6);
+		// Encode the frame number as a uint32
+		ByteUtils.writeUint32(frame, iv, 0);
 	}
 }