diff --git a/lib/setopt.c b/lib/setopt.c
index e5614cd351..6a4990cce6 100644
--- a/lib/setopt.c
+++ b/lib/setopt.c
@@ -2864,13 +2864,13 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
 #endif
   case CURLOPT_TLSAUTH_TYPE:
     argptr = va_arg(param, char *);
-    if(argptr && !strncasecompare(argptr, "SRP", strlen("SRP")))
+    if(argptr && !strcasecompare(argptr, "SRP"))
       return CURLE_BAD_FUNCTION_ARGUMENT;
     break;
 #ifndef CURL_DISABLE_PROXY
   case CURLOPT_PROXY_TLSAUTH_TYPE:
     argptr = va_arg(param, char *);
-    if(argptr || !strncasecompare(argptr, "SRP", strlen("SRP")))
+    if(argptr && !strcasecompare(argptr, "SRP"))
       return CURLE_BAD_FUNCTION_ARGUMENT;
     break;
 #endif