'char' argument to islower must be converted to 'unsigned char'
diff --git a/apps/enc.c b/apps/enc.c
index f43bb02..95aae9a 100644
--- a/apps/enc.c
+++ b/apps/enc.c
@@ -87,7 +87,7 @@
 	BIO *bio=bio_;
 	static int n;
 
-	if(!islower(*name->name))
+	if(!islower((unsigned char)*name->name))
 		return;
 
 	BIO_printf(bio,"-%-25s",name->name);