diff --git a/library/ripemd160.c b/library/ripemd160.c
index 260fee6..b85b117 100644
--- a/library/ripemd160.c
+++ b/library/ripemd160.c
@@ -46,6 +46,8 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST */
 
+#if !defined(MBEDTLS_RIPEMD160_ALT)
+
 /*
  * 32-bit integer manipulation macros (little endian)
  */
@@ -393,6 +395,8 @@
     return( 0 );
 }
 
+#endif /* ! MBEDTLS_RIPEMD160_ALT */
+
 /*
  * output = RIPEMD-160( input buffer )
  */