DES加解密

    /// <summary>
    /// DES加密
    /// </summary>
    /// <param name="data"></param>
    /// <param name="key"></param>
    /// <param name="iv"></param>
    public static string DesEncode(string data, string key, string iv)
    {
        byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);
        byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);

        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
        int i = cryptoProvider.KeySize;
        MemoryStream ms = new MemoryStream();
        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);

        StreamWriter sw = new StreamWriter(cst);
        sw.Write(data);
        sw.Flush();
        cst.FlushFinalBlock();
        sw.Flush();
        return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);

    }

    /// <summary>
    /// DES解密
    /// </summary>
    /// <param name="data"></param>
    /// <param name="key"></param>
    /// <param name="iv"></param>
    public static string DesDecode(string data, string key, string iv)
    {
        byte[] byKey = ASCIIEncoding.ASCII.GetBytes(key);
        byte[] byIV = ASCIIEncoding.ASCII.GetBytes(iv);

        byte[] byEnc;
        try
        {
            byEnc = Convert.FromBase64String(data);
        }
        catch
        {
            return null;
        }

        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
        MemoryStream ms = new MemoryStream(byEnc);
        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
        StreamReader sr = new StreamReader(cst);
        return sr.ReadToEnd();
    }