MD5加密、字节与字符串转换、对ToString("X2 ")的理解

        public static string md5(string str)
        {
            //将字符串编码为字节序列
            byte[] bt = Encoding.UTF8.GetBytes(str);
            //创建默认实现的实例
            var md5 = MD5.Create();
            //计算指定字节数组的哈希值。
            var md5bt = md5.ComputeHash(bt);
            //将byte数组转换为字符串
            StringBuilder builder = new StringBuilder();
            foreach (var item in md5bt)
            {
                builder.Append(item.ToString("X2"));
            }
            string md5Str = builder.ToString();
            return builder.ToString();
        }

 /// <summary>
        /// 将byte型转换为字符串
        /// </summary>
        /// <param name="arrInput">byte型数组</param>
        /// <returns>目标字符串</returns>
        private string ByteArrayToString(byte[] arrInput)
        {
            int i;
            StringBuilder sOutput = new StringBuilder(arrInput.Length);
            for (i = 0; i < arrInput.Length; i++)
            {
                sOutput.Append(arrInput[i].ToString("X2"));  
            }
            //将此实例的值转换为System.String
            return sOutput.ToString();
        }

 

        /// <summary>
        /// 对接收到的数据进行解包（将接收到的byte型数组解包为Unicode字符串）
        /// </summary>
        /// <param name="recbytes">byte型数组</param>
        /// <returns>Unicode编码的字符串</returns>
        public string disPackage(byte[] recbytes)
        {
            string temp = "";
            foreach (byte b in recbytes)
                temp += b.ToString("X2") + " ";//ToString("X2") 为C#中的字符串格式控制符
            return temp;
        }

public static string md5(string str)
        {
            //将字符串编码为字节序列
            byte[] bt = Encoding.UTF8.GetBytes(str);
            //创建默认实现的实例
            var md5 = MD5.Create();
            //计算指定字节数组的哈希值。
            var md5bt = md5.ComputeHash(bt);
            //将byte数组转换为字符串
            StringBuilder builder = new StringBuilder();
            foreach (var item in md5bt)
            {
                builder.Append(item.ToString("X2"));
            }
            string md5Str = builder.ToString();
            return builder.ToString();
        }