C#加密：DES加密

/// <summary>
/// .Net DES加密解密帮助类
/// </summary>
public class CryptoDESHelper
{
    /// <summary>
    /// Des默认密钥向量
    /// </summary>
    public static byte[] DesIv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
    /// <summary>
    /// Des加解密钥必须8位
    /// </summary>
    public const string DesKey = "hansjcy2";
    /// <summary>
    /// 获取Des8位密钥
    /// </summary>
    /// <param name="key">Des密钥字符串</param>
    /// <returns>Des8位密钥</returns>
    static byte[] GetDesKey(string key)
    {
        if (string.IsNullOrEmpty(key))
        {
            throw new ArgumentNullException("key", "Des密钥不能为空");
        }
        if (key.Length > 8)
        {
            key = key.Substring(0, 8);
        }
        if (key.Length < 8)
        {
            // 不足8补全
            key = key.PadRight(8, '0');
        }
        return Encoding.UTF8.GetBytes(key);
    }
    /// <summary>
    /// Des加密
    /// </summary>
    /// <param name="source">源字符串</param>
    /// <param name="key">des密钥，长度必须8位</param>
    /// <param name="iv">密钥向量</param>
    /// <returns>加密后的字符串</returns>
    public static string EncryptDes(string source, string key, byte[] iv)
    {
        using (DESCryptoServiceProvider desProvider = new DESCryptoServiceProvider())
        {
            byte[] rgbKeys = GetDesKey(key),
                rgbIvs = iv,
                inputByteArray = Encoding.UTF8.GetBytes(source);
            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, desProvider.CreateEncryptor(rgbKeys, rgbIvs), CryptoStreamMode.Write))
                {
                    cryptoStream.Write(inputByteArray, 0, inputByteArray.Length);
                    cryptoStream.FlushFinalBlock();
                    // 1.第一种
                    return Convert.ToBase64String(memoryStream.ToArray());

                    // 2.第二种
                    //StringBuilder result = new StringBuilder();
                    //foreach (byte b in memoryStream.ToArray())
                    //{
                    //    result.AppendFormat("{0:X2}", b);
                    //}
                    //return result.ToString();
                }
            }
        }
    }
    /// <summary>
    /// Des解密
    /// </summary>
    /// <param name="source">源字符串</param>
    /// <param name="key">des密钥，长度必须8位</param>
    /// <param name="iv">密钥向量</param>
    /// <returns>解密后的字符串</returns>
    public static string DecryptDes(string source, string key, byte[] iv)
    {
        using (DESCryptoServiceProvider desProvider = new DESCryptoServiceProvider())
        {
            byte[] rgbKeys = GetDesKey(key),
                rgbIvs = iv,
                inputByteArray = Convert.FromBase64String(source);
            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, desProvider.CreateDecryptor(rgbKeys, rgbIvs), CryptoStreamMode.Write))
                {
                    cryptoStream.Write(inputByteArray, 0, inputByteArray.Length);
                    cryptoStream.FlushFinalBlock();
                    return Encoding.UTF8.GetString(memoryStream.ToArray());
                }
            }
        }
    }
}