/// <summary>        /// 签名MD5        /// </summary>        /// <param name="s"></param>        /// <returns></returns>        public static String MD5(String s)        {            char[] hexDigits = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘,					‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘ };            try            {                byte[] btInput = System.Text.Encoding.UTF8.GetBytes(s);                // 获得MD5摘要算法的 MessageDigest 对象              System.Security.Cryptography.MD5 mdInst = System.Security.Cryptography.MD5.Create();                // 使用指定的字节更新摘要                mdInst.ComputeHash(btInput);                // 获得密文                byte[] md = mdInst.Hash;                // 把密文转换成十六进制的字符串形式                int j = md.Length;                char[] str = new char[j * 2];                int k = 0;                for (int i = 0; i < j; i++)                {                    byte byte0 = md[i];                    str[k++] = hexDigits[(int)(((byte)byte0) >> 4) & 0xf];                    str[k++] = hexDigits[byte0 & 0xf];                }                return new string(str);//编码转换            }            catch (Exception e)            {                writeLogs.writelog("调用签名md5异常:"+e.Message);                return null;            }        }