diff --git a/ssl/ssl_cipher.cc b/ssl/ssl_cipher.cc
index 7c4c034..391944a 100644
--- a/ssl/ssl_cipher.cc
+++ b/ssl/ssl_cipher.cc
@@ -1002,8 +1002,7 @@
         rule = CIPHER_ADD;
         l++;
         continue;
-      } else if (!(ch >= 'a' && ch <= 'z') && !(ch >= 'A' && ch <= 'Z') &&
-                 !(ch >= '0' && ch <= '9')) {
+      } else if (!OPENSSL_isalnum(ch)) {
         OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_OPERATOR_IN_GROUP);
         return false;
       } else {
@@ -1056,8 +1055,7 @@
       ch = *l;
       buf = l;
       buf_len = 0;
-      while ((ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9') ||
-             (ch >= 'a' && ch <= 'z') || ch == '-' || ch == '.' || ch == '_') {
+      while (OPENSSL_isalnum(ch) || ch == '-' || ch == '.' || ch == '_') {
         ch = *(++l);
         buf_len++;
       }