.NET MD5加密解密代碼解析

string JiaMi = Md5Encrypt(LoginPwd);
 string JieMi = Md5Decrypt(JiaMi);

 #region MD5加密
 /// <summary> 
 /// MD5加密 
 /// </summary> 
 /// <param name="strSource">需要加密的字符串</param> 
 /// <returns>MD5加密后的字符串</returns> 
 public static string Md5Encrypt(string strSource)
 {
 //把字符串放到byte數(shù)組中 
 byte[] bytIn = System.Text.Encoding.Default.GetBytes(strSource);
 //建立加密對象的密鑰和偏移量 
 byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定義偏移量 
 byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定義密鑰 
 //實例DES加密類 
 DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider();
 mobjCryptoService.Key = iv;
 mobjCryptoService.IV = key;
 ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
 //實例MemoryStream流加密密文件 
 System.IO.MemoryStream ms = new System.IO.MemoryStream();
 CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
 cs.Write(bytIn, 0, bytIn.Length);
 cs.FlushFinalBlock();
 return System.Convert.ToBase64String(ms.ToArray());
 }
 #endregion


 #region MD5解密
 /// <summary> 
 /// MD5解密 
 /// </summary> 
 /// <param name="Source">需要解密的字符串</param> 
 /// <returns>MD5解密后的字符串</returns> 
 public static string Md5Decrypt(string Source)
 {
 //將解密字符串轉(zhuǎn)換成字節(jié)數(shù)組 
 byte[] bytIn = System.Convert.FromBase64String(Source);
 //給出解密的密鑰和偏移量，密鑰和偏移量必須與加密時的密鑰和偏移量相同 
 byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定義偏移量 
 byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定義密鑰 
 DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider();
 mobjCryptoService.Key = iv;
 mobjCryptoService.IV = key;
 //實例流進(jìn)行解密 
 System.IO.MemoryStream ms = new System.IO.MemoryStream(bytIn, 0, bytIn.Length);
 ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
 CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
 StreamReader strd = new StreamReader(cs, Encoding.Default);
 return strd.ReadToEnd();
 }
 #endregion