diff --git a/library/md4.c b/library/md4.c
index 9062358..b71d2c9 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -90,6 +90,12 @@
     mbedtls_zeroize( ctx, sizeof( mbedtls_md4_context ) );
 }
 
+void mbedtls_md4_clone( mbedtls_md4_context *dst,
+                        const mbedtls_md4_context *src )
+{
+    *dst = *src;
+}
+
 /*
  * MD4 context setup
  */