有没有大佬来看看这段.net 代码怎么转为 PHP

public static string MD5Encrypt(string input) { System.Text.Encoding chset = System.Text.Encoding.GetEncoding("GBK"); MD5 md5 = new MD5CryptoServiceProvider(); byte[] t = md5.ComputeHash(chset.GetBytes(input)); StringBuilder sb = new StringBuilder(32); for (int i = 0; i < t.Length; i++) sb.Append(t[i].ToString("x").PadLeft(2, '0')); return sb.ToString(); }