一个通用的加密、解密类

public class Encrypt
{
    /// <summary>
    /// 加密
    /// </summary>
    /// <param name="str">待加密的明文字符串</param>
    /// <param name="key">密钥</param>
    /// <returns>加密后的字符串</returns>
    public static string EncryptString(string str, string key)
    {
        byte[] bStr = (new UnicodeEncoding()).GetBytes(str);
        byte[] bKey = (new UnicodeEncoding()).GetBytes(key);

        for (int i = 0; i < bStr.Length; i += 2)
        {
            for (int j = 0; j < bKey.Length; j += 2)
            {
                bStr[i] = Convert.ToByte(bStr[i] ^ bKey[j]);
            }
        }

        return (new UnicodeEncoding()).GetString(bStr).TrimEnd('\0');
    }

    /// <summary>
    /// 解密
    /// </summary>
    /// <param name="str">待解密的密文字符串</param>
    /// <param name="key">密钥</param>
    /// <returns>解密后的明文</returns>
    public static string DecryptString(string str, string key)
    {
        return EncryptString(str, key);
    }
}