diff --git a/include/polarssl/ripemd160.h b/include/polarssl/ripemd160.h
index 47a73bd..02a92f5 100644
--- a/include/polarssl/ripemd160.h
+++ b/include/polarssl/ripemd160.h
@@ -40,6 +40,10 @@
 
 #define POLARSSL_ERR_RIPEMD160_FILE_IO_ERROR              -0x0074  /**< Read/write error in file. */
 
+#if !defined(POLARSSL_RIPEMD160_ALT)
+// Regular implementation
+//
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -83,6 +87,21 @@
  */
 void ripemd160_finish( ripemd160_context *ctx, unsigned char output[20] );
 
+/* Internal use */
+void ripemd160_process( ripemd160_context *ctx, const unsigned char data[64] );
+
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* POLARSSL_RIPEMD160_ALT */
+#include "ripemd160.h"
+#endif /* POLARSSL_RIPEMD160_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * \brief          Output = RIPEMD-160( input buffer )
  *
@@ -160,9 +179,6 @@
  */
 int ripemd160_self_test( int verbose );
 
-/* Internal use */
-void ripemd160_process( ripemd160_context *ctx, const unsigned char data[64] );
-
 #ifdef __cplusplus
 }
 #endif