diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 16b3200..a716710 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -804,7 +804,9 @@
     else
     {
         sha2_context sha2;
+#if defined(POLARSSL_SHA4_C)
         sha4_context sha4;
+#endif
 
         n = ssl->in_hslen - ( end - p ) - 8;