<!DOCTYPE html>
<html>
<body>

<?php
$str = "Shanghai";
echo md5($str);
?>   
  
</body>
</html>

输出

5466ee572bcbc75830d044e66ab429bc

 

参考:

https://www.w3school.com.cn/tiy/s.asp?f=demo_php_func_string_md5