diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 8e5c047..0db8b6b 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -3875,8 +3875,8 @@
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
         }
-        if( *p++ != MBEDTLS_CHAR_1( len ) ||
-            *p++ != MBEDTLS_CHAR_0( len ) ){
+        if( *p++ != MBEDTLS_BYTE_1( len ) ||
+            *p++ != MBEDTLS_BYTE_0( len ) ){
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
         }