diff --git a/library/sha512.c b/library/sha512.c
index f09b0f7..3daf080 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -150,6 +150,12 @@
     mbedtls_zeroize( ctx, sizeof( mbedtls_sha512_context ) );
 }
 
+void mbedtls_sha512_clone( mbedtls_sha512_context *dst,
+                           const mbedtls_sha512_context *src )
+{
+    *dst = *src;
+}
+
 /*
  * SHA-512 context setup
  */