基于C#对用户密码使用MD5加密与解密

 /// 
 /// 16位MD5加密 /// 
 ///  ///  public static string MD5Encrypt16(string password) { var md5 = new MD5CryptoServiceProvider(); string t2 = BitConverter.ToString(md5.ComputeHash(Encoding.Default.GetBytes(password)), 4, 8); t2 = t2.Replace("-", ""); return t2; } 

 /// 
 /// 32位MD5加密 /// 
 ///  ///  public static string MD5Encrypt32(string password) { string cl = password; string pwd = ""; MD5 md5 = MD5.Create(); //实例化一个md5对像 // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　 byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl)); // 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得 for (int i = 0; i 

 public static string MD5Encrypt64(string password) { string cl = password; //string pwd = ""; MD5 md5 = MD5.Create(); //实例化一个md5对像 // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　 byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl)); return Convert.ToBase64String(s); }

 /// 
 /// 加密用户密码 /// 
 /// 密码 /// 加密位数 /// 加密密码 public static string md5(string password, int codeLength) { if (!string.IsNullOrEmpty(password)) { // 16位MD5加密（取32位加密的9~25字符） if (codeLength == 16) { return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(password, "MD5").ToLower().Substring(8, 16); } // 32位加密 if (codeLength == 32) { return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(password, "MD5").ToLower(); } } return string.Empty; } 

 /// 
 /// 登陆 /// 
 public Model.UserInfo UserLogOn(string USERID, string pwd, out string statusCode) { //假设已经通过用户ID获取到UserInfo的Model对象 Model.UserInfo model = GetModel(USERID); if (model != null) { if (model.PASSWORD == MD5Encrypt64(pwd)) { statusCode = "登陆成功"; } else { statusCode = “密码错误”； } } else { statusCode = "用户不存在！"; model = null; } return model; } 

 /// 
 /// DES数据加密 /// 
 /// 目标值 /// 密钥 /// 加密值 public static string Encrypt(string targetValue, string key) { if (string.IsNullOrEmpty(targetValue)) { return string.Empty; } var returnValue = new StringBuilder(); var des = new DESCryptoServiceProvider(); byte[] inputByteArray = Encoding.Default.GetBytes(targetValue); // 通过两次哈希密码设置对称算法的初始化向量 des.Key = Encoding.ASCII.GetBytes(FormsAuthentication.HashPasswordForStoringInConfigFile (FormsAuthentication.HashPasswordForStoringInConfigFile(key, "md5"). Substring(0, 8), "sha1").Substring(0, 8)); // 通过两次哈希密码设置算法的机密密钥 des.IV = Encoding.ASCII.GetBytes(FormsAuthentication.HashPasswordForStoringInConfigFile (FormsAuthentication.HashPasswordForStoringInConfigFile(key, "md5") .Substring(0, 8), "md5").Substring(0, 8)); var ms = new MemoryStream(); var cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write); cs.Write(inputByteArray, 0, inputByteArray.Length); cs.FlushFinalBlock(); foreach (byte b in ms.ToArray()) { returnValue.AppendFormat("{0:X2}", b); } return returnValue.ToString(); }

 /// 
 /// DES数据解密 /// 
 ///  ///  ///  public static string Decrypt(string targetValue, string key) { if (string.IsNullOrEmpty(targetValue)) { return string.Empty; } // 定义DES加密对象 var des = new DESCryptoServiceProvider(); int len = targetValue.Length / 2; var inputByteArray = new byte[len]; int x, i; for (x = 0; x