.net加密解密

前几天因为要做点加密解密的东西来保存配置信息,找了很久终于找到一个比较常用的类,贴出来.共享...
里面已经有两种加密解密的算法:DES, Rijndael
加需要的,去查一下msdn,自己加啦..

    public class SymmCrypto
    { 
        public enum SymmProvEnum : int
        {
            DES, Rijndael
        }

        private static SymmetricAlgorithm mobjCryptoService;
 
        public static void ChangeCryptoService(SymmProvEnum NetSelected)
        {
            switch (NetSelected)
            {
                case SymmProvEnum.DES:
                    mobjCryptoService = new DESCryptoServiceProvider();
                    break; 
                case SymmProvEnum.Rijndael:
                    mobjCryptoService = new RijndaelManaged();
                    break;
            }
        }

        public static void ChangeCryptoService(SymmetricAlgorithm ServiceProvider)
        {
            mobjCryptoService = ServiceProvider;
        }

        private static byte[] GetLegalKey(string Key)
        {
            string sTemp;
            if (mobjCryptoService.LegalKeySizes.Length > 0)
            {
                int lessSize = 0, moreSize = mobjCryptoService.LegalKeySizes[0].MinSize; 
                while (Key.Length * 8 > moreSize)
                {
                    lessSize = moreSize;
                    moreSize += mobjCryptoService.LegalKeySizes[0].SkipSize;
                }
                sTemp = Key.PadRight(moreSize / 8, ' ');
            }
            else
                sTemp = Key;
 
            return ASCIIEncoding.ASCII.GetBytes(sTemp);
        }

        static void SetmobjCryptoService()
        {
            if (null == mobjCryptoService)
                mobjCryptoService = new RijndaelManaged();
        }

        public static string Encrypting(string Source, string Key)
        {
            SetmobjCryptoService();

            byte[] bytIn = System.Text.ASCIIEncoding.ASCII.GetBytes(Source); 
            System.IO.MemoryStream ms = new System.IO.MemoryStream();

            byte[] bytKey = GetLegalKey(Key);
 
            mobjCryptoService.Key = bytKey;
            mobjCryptoService.IV = bytKey;
 
            ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
 
            CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
 
            cs.Write(bytIn, 0, bytIn.Length);
            cs.FlushFinalBlock();
 
            byte[] bytOut = ms.GetBuffer();
            int i = 0;
            for (i = 0; i < bytOut.Length; i++)
                if (bytOut[i] == 0)
                    break;
 
            return System.Convert.ToBase64String(bytOut, 0, i);
        }

        public static string Decrypting(string Source, string Key)
        {
            SetmobjCryptoService();

            byte[] bytIn = System.Convert.FromBase64String(Source); 
            System.IO.MemoryStream ms = new System.IO.MemoryStream(bytIn, 0, bytIn.Length);

            byte[] bytKey = GetLegalKey(Key);

            mobjCryptoService.Key = bytKey;
            mobjCryptoService.IV = bytKey;
 
            ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
 
            CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
 
            System.IO.StreamReader sr = new System.IO.StreamReader(cs);
            return sr.ReadToEnd();
        }
    }