基於System.Security.Cryptography.SymmetricAlgorithm 的私鑰加密解密幫助類

public class SymetricAlgrithmCryptographyHelper<ST, ET>
        where ST : SymmetricAlgorithm, new()
        where ET : Encoding, new()
    {
        /// <summary>
        /// KeySault is to fill the key if input key sting is too short
        /// </summary>
        public byte[] keySault = new byte[] { 0x43, 0x87, 0x23, 0x72 };

        /// <summary>
        /// this is used to generate the key according to the different Algrithm
        /// </summary>
        /// <param name="key">from user secret key</param>
        /// <param name="size">how many bytes</param>
        /// <returns></returns>
        private byte[] GenerateIndentification(byte[] key, int size)
        {
            PasswordDeriveBytes pdb =
              new PasswordDeriveBytes(key,
              keySault);

            return pdb.GetBytes(size);
        }

        private ST sa { get { return new ST(); } }
        private ET ecoding;

        public SymetricAlgrithmCryptographyHelper()
        {
            //this.sa = new ST();
            this.ecoding = new ET();
        }

        public byte[] Encrypt(string key, byte[] input)
        {
            byte[] keyBytes = this.ecoding.GetBytes(key);
            return Encrypt(keyBytes, input);
        }

        public byte[] Encrypt(byte[] key, byte[] input)
        {
            MemoryStream ms = new MemoryStream();
            SymmetricAlgorithm cryptor = this.sa;
            cryptor.Key = this.GenerateIndentification(key, cryptor.KeySize / 8);
            cryptor.IV = this.GenerateIndentification(key, cryptor.BlockSize / 8);
            CryptoStream cs = new CryptoStream(ms,
              cryptor.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(input, 0, input.Length);
            cs.Close();
            return ms.ToArray();
        }

        public byte[] Decrypt(string key, byte[] input)
        {
            byte[] keyBytes = this.ecoding.GetBytes(key);
            return Decrypt(keyBytes, input);
        }

        public byte[] Decrypt(byte[] key, byte[] input)
        {
            MemoryStream ms = new MemoryStream();
            SymmetricAlgorithm cryptor = this.sa;
            cryptor.Key = this.GenerateIndentification(key, cryptor.KeySize / 8);
            cryptor.IV = this.GenerateIndentification(key, cryptor.BlockSize / 8);
            CryptoStream cs = new CryptoStream(ms,
              cryptor.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(input, 0, input.Length);
            cs.Close();
            return ms.ToArray();
        }

        /// <summary>
        /// Encrypt to base 64 string
        /// </summary>
        /// <param name="key">secret key</param>
        /// <param name="input">data</param>
        /// <returns>Encrypted data string</returns>
        public string EncryptToBase64String(string key, string input)
        {
            return Convert.ToBase64String(Encrypt(key, this.ecoding.GetBytes(input)));
        }

        /// <summary>
        /// Decrypt to original string data
        /// </summary>
        /// <param name="key">secret key</param>
        /// <param name="input">data</param>
        /// <returns>Decrypted data</returns>
        public string DecryptFromBase64String(string key, string input)
        {
            return this.ecoding.GetString(Decrypt(key, Convert.FromBase64String(input)));
        }

    }

使用：

//key
            string sSecretKey = "DECPKEY2013";
            //內容
            string facetexe = "realcontext";
            //選取算法實現類，編碼格式
            SymetricAlgrithmCryptographyHelper<AesCryptoServiceProvider, UTF8Encoding> helper = new SymetricAlgrithmCryptographyHelper<AesCryptoServiceProvider, UTF8Encoding>();
            //加密成64位字符 “CCHq7sCXBkUHgYjWfA4qDQ==”
            string encryped = helper.EncryptToBase64String(sSecretKey, facetexe);
            //用key解密
            string faceback = helper.DecryptFromBase64String(sSecretKey, encryped);