diff --git a/src/bin/cipherbench.rs b/src/bin/cipherbench.rs
index 590c1024..7238c09b 100644
--- a/src/bin/cipherbench.rs
+++ b/src/bin/cipherbench.rs
@@ -69,7 +69,7 @@ fn main() -> Result<(), Error> {
         openssl::symm::encrypt_aead(
             cipher,
             &key,
-            Some(&iv),
+            Some(&iv[..12]),
             b"",
             &input,
             &mut tag).unwrap();