C#實現字符串DES加密和解密方法

public class Encrypt
{
  //默認密鑰向量
  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">加密密鑰,要求為8位</param>
  /// <returns>加密成功返回加密后的字符串，失敗返回源串</returns>
  public static string EncryptDES(string encryptString, string encryptKey)
  {
      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());
  }

  /// <summary>
  /// DES解密字符串
  /// </summary>
  /// <param name="decryptString">待解密的字符串</param>
  /// <param name="decryptKey">解密密鑰,要求為8位,和加密密鑰相同</param>
  /// <returns>解密成功返回解密后的字符串，失敗返源串</returns>
  public static string DecryptDES(string decryptString, string decryptKey)
  {
    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());
  }
}