C#中加密与解密

      早上起来，头一阵疼痛，昨天睡了一天，今天再也不能这样睡下去了，于是洗漱完后往公司赶去，到公司后冷冷静静的只有我一个人，哎，又多愁善感了，闲话不多说，今天要分享的是C#中加密与解密的运算，代码如下：

        /// <summary>
        /// 创建key
        /// </summary>
        /// <returns></returns>
        public static string GenerateKey()
        {
            System.Security.Cryptography.DESCryptoServiceProvider desCrypto = (System.Security.Cryptography.DESCryptoServiceProvider)System.Security.Cryptography.DESCryptoServiceProvider.Create();
            return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
        }
         /// <summary>
         /// MD5加密
      /// </summary>
        /// <param name="text">需要加密的字符串</param>
        /// <param name="key">加密需要的KEY</param>
        /// <returns>返回加密后的字符串</returns>
        public static string MD5Encrypt(string text, string key)
        {
            try
            {
                System.Security.Cryptography.DESCryptoServiceProvider des = new System.Security.Cryptography.DESCryptoServiceProvider();
                //把字符串放到byte数组中
                byte[] inputByteArray = Encoding.Default.GetBytes(text);
                //建立加密对象的密钥和偏移量
                //使得输入密码必须输入英文文本
                des.Key = ASCIIEncoding.ASCII.GetBytes(key);
                des.IV = ASCIIEncoding.ASCII.GetBytes(key);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                System.Security.Cryptography.CryptoStream cs = new System.Security.Cryptography.CryptoStream(ms, des.CreateEncryptor(), System.Security.Cryptography.CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                StringBuilder ret = new StringBuilder();
                foreach (byte b in ms.ToArray())
                {
                    ret.AppendFormat("{0:X2}", b);
                }
                ret.ToString();
                return ret.ToString();
            }
            catch
            {
                return String.Empty;
            }
        
        
        }
         /// <summary>
         /// MD5解密
      /// </summary>
        /// <param name="text">需要解密的字符串</param>
        /// <param name="key">解密需要的KEY</param>
        /// <returns>返回解密后的字符串</returns>
        public static string MD5Decrypt(string text, string key)
        {
            try
            {
                System.Security.Cryptography.DESCryptoServiceProvider des = new System.Security.Cryptography.DESCryptoServiceProvider();

                byte[] inputByteArray = new byte[text.Length / 2];
                for (int x = 0; x < text.Length / 2; x++)
                {
                    int i = (Convert.ToInt32(text.Substring(x * 2, 2), 16));
                    inputByteArray[x] = (byte)i;
                }
                //建立加密对象的密钥和偏移量，此值重要，不能修改
                des.Key = ASCIIEncoding.ASCII.GetBytes(key);
                des.IV = ASCIIEncoding.ASCII.GetBytes(key);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                System.Security.Cryptography.CryptoStream cs = new System.Security.Cryptography.CryptoStream(ms, des.CreateDecryptor(), System.Security.Cryptography.CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象
                StringBuilder ret = new StringBuilder();

                return System.Text.Encoding.Default.GetString(ms.ToArray());
            }
            catch
            {
                return String.Empty;
            }
        }

    调用端的代码：

        /// <summary>
        /// 生成加密与解密的KEY
        /// </summary>
        String MD5KEY = GenerateKey();
        /// <summary>
        /// 调用加密的方法，对文本框中的字符串进行加密
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            
            textBox2.Text = MD5Encrypt(textBox1.Text, MD5KEY);
            
        }
        /// <summary>
        /// 调用解密的方法，对加密后的字符串进行解密
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            textBox3.Text = MD5Decrypt(textBox2.Text, MD5KEY);
        }

     这里需要注意的是，加密用的MD5KEY和解密用的MD5KEY必须一样，否则无法正常解密！