diff --git a/lualib-src/lua-crypt.c b/lualib-src/lua-crypt.c
index 6ddb246e..400322a5 100644
--- a/lualib-src/lua-crypt.c
+++ b/lualib-src/lua-crypt.c
@@ -494,7 +494,7 @@ static int
 lfromhex(lua_State *L) {
 	size_t sz = 0;
 	const char * text = luaL_checklstring(L, 1, &sz);
-	if (sz & 2) {
+	if (sz & 1) {
 		return luaL_error(L, "Invalid hex text size %d", (int)sz);
 	}
 	char tmp[SMALL_CHUNK];