M5加密字符串

private string GetMD5str(string oldStr)
        {
            //将输入转换为ASCII 字符编码
            ASCIIEncoding enc = new ASCIIEncoding();
            //将字符串转换为字节数组
            byte[] buffer = enc.GetBytes(oldStr);
            //创建MD5实例
            MD5 md5 = new MD5CryptoServiceProvider();
            //进行MD5加密
            byte[] hash = md5.ComputeHash(buffer);
            StringBuilder sb = new StringBuilder();
            //拼装加密后的字符
            for (int i = ; i < hash.Length; i++)
            {
                sb.AppendFormat("{0:x2}", hash[i]);
            }
            //输出加密后的字符串
            return sb.ToString();
        }