diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index c419665..17f9d0e 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -538,7 +538,7 @@
 #if defined(MBEDTLS_POLY1305_C)
     if ( todo.poly1305 )
     {
-        TIME_AND_TSC( "Poly1305", mbedtls_poly1305_mac( buf, BUFSIZE, buf, buf ) );
+        TIME_AND_TSC( "Poly1305", mbedtls_poly1305_mac( buf, buf, BUFSIZE, buf ) );
     }
 #endif