diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
index f9765c99f..f03470476 100644
--- a/library/ssl_ciphersuites.c
+++ b/library/ssl_ciphersuites.c
@@ -2384,7 +2384,7 @@ const char *mbedtls_ssl_get_ciphersuite_name(
     if( ciphersuite_id == single_suite_id )
         return( MBEDTLS_SSL_SUITE_NAME( MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE ) );
 
-    return( NULL );
+    return( "unknown" );
 }
 
 int mbedtls_ssl_get_ciphersuite_id( const char *ciphersuite_name )