C#实现的字符串加密和解密方法

public class Encrypt  {  //默认密钥向量  private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };             /// <summary>  /// DES加密字符串  /// </summary>  /// <param name="encryptString">待加密的字符串</param>  /// <param name="encryptKey">加密密钥,要求为8位</param>  /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>  public static string EncryptDES(string encryptString, string encryptKey)  {  try  {  byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));  byte[] rgbIV = Keys;  byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);  DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();  MemoryStream mStream = new MemoryStream();  CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);  cStream.Write(inputByteArray, 0, inputByteArray.Length);  cStream.FlushFinalBlock();  return Convert.ToBase64String(mStream.ToArray());  }  catch  {  return encryptString;  }  }        /// <summary>  /// DES解密字符串  /// </summary>  /// <param name="decryptString">待解密的字符串</param>  /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>  /// <returns>解密成功返回解密后的字符串，失败返源串</returns>  public static string DecryptDES(string decryptString, string decryptKey)  {  try  {  byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);  byte[] rgbIV = Keys;  byte[] inputByteArray = Convert.FromBase64String(decryptString);  DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();  MemoryStream mStream = new MemoryStream();  CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);  cStream.Write(inputByteArray, 0, inputByteArray.Length);  cStream.FlushFinalBlock();  return Encoding.UTF8.GetString(mStream.ToArray());  }  catch  {  return decryptString;  }  }  }