AES加密

AES加密:雙向，能夠加密，也能夠解密

1.AES加密幫助類

    /// <summary>
    /// AES對稱加密解密類
    /// </summary>
    public class AESHelper
    {
        #region 成員變量
        /// <summary>
        /// 密鑰
        /// </summary>
        private static string _passwd = "ihlih*0037JOHT*)(PIJY*(()JI^)IO%";

        /// <summary>
        /// 密鑰位數
        /// </summary>
        private const int _passwdLength = 32;

        /// <summary>
        /// 運算模式
        /// </summary>
        private static CipherMode _cipherMode = CipherMode.ECB;
        /// <summary>
        /// 填充模式
        /// </summary>
        private static PaddingMode _paddingMode = PaddingMode.PKCS7;
        /// <summary>
        /// 字符串採用的編碼
        /// </summary>
        private static Encoding _encoding = Encoding.UTF8;
        #endregion

        #region 輔助方法
        /// <summary>
        /// 獲取byte密鑰數據
        /// </summary>
        /// <param name="password">密碼</param>
        /// <returns></returns>
        private static byte[] GetKeyArray(string password)
        {
            if (password == null)
            {
                password = string.Empty;
            }

            if (password.Length < _passwdLength)
            {
                password = password.PadRight(_passwdLength, '0');
            }
            else if (password.Length > _passwdLength)
            {
                password = password.Substring(0, _passwdLength);
            }

            return _encoding.GetBytes(password);
        }

        /// <summary>
        /// 將字符數組轉換成字符串
        /// </summary>
        /// <param name="inputData"></param>
        /// <returns></returns>
        private static string ConvertByteToString(byte[] inputData)
        {
            StringBuilder sb = new StringBuilder(inputData.Length * 2);
            foreach (var b in inputData)
            {
                sb.Append(b.ToString("X2"));
            }
            return sb.ToString();
        }

        /// <summary>
        /// 將字符串轉換成字符數組
        /// </summary>
        /// <param name="inputString"></param>
        /// <returns></returns>
        private static byte[] ConvertStringToByte(string inputString)
        {
            if (inputString == null || inputString.Length < 2)
            {
                throw new ArgumentException();
            }

            if ((inputString.Length % 2) != 0)
            {
                inputString += " ";
            }

            int l = inputString.Length / 2;
            byte[] result = new byte[l];
            for (int i = 0; i < l; ++i)
            {
                result[i] = Convert.ToByte(inputString.Substring(2 * i, 2), 16);
            }

            return result;
        }
        #endregion

        #region 加密
        /// <summary>
        /// 加密字節數據
        /// </summary>
        /// <param name="inputData">要加密的字節數據</param>
        /// <param name="password">密碼</param>
        /// <returns></returns>
        public static byte[] Encrypt(byte[] inputData, string password)
        {
            using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
            {
                aes.Key = GetKeyArray(password);
                aes.Mode = _cipherMode;
                aes.Padding = _paddingMode;
                ICryptoTransform transform = aes.CreateEncryptor();
                byte[] data = transform.TransformFinalBlock(inputData, 0, inputData.Length);
                aes.Clear();
                return data;
            }
        }

        /// <summary>
        /// 加密字符串(加密爲16進制字符串)
        /// </summary>
        /// <param name="inputString">要加密的字符串</param>
        /// <param name="password">密碼</param>
        /// <returns></returns>
        public static string Encrypt(string inputString, string password)
        {
            if (string.IsNullOrWhiteSpace(inputString) || string.IsNullOrWhiteSpace(password))
            {
                return string.Empty;
            }

            byte[] toEncryptArray = _encoding.GetBytes(inputString);
            byte[] result = Encrypt(toEncryptArray, password);
            return ConvertByteToString(result);
        }

        /// <summary>
        /// 字符串加密(加密爲16進制字符串)
        /// </summary>
        /// <param name="inputString">須要加密的字符串</param>
        /// <returns>加密後的字符串</returns>
        public static string EncryptString(string inputString)
        {
            if (string.IsNullOrWhiteSpace(_passwd))
            {
                throw new ArgumentException("密鑰不能爲空");
            }
            return Encrypt(inputString, _passwd);
        }
        #endregion

        #region 解密
        /// <summary>
        /// 解密字節數組
        /// </summary>
        /// <param name="inputData">要解密的字節數據</param>
        /// <param name="password">密碼</param>
        /// <returns></returns>
        public static byte[] Decrypt(byte[] inputData, string password)
        {
            using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
            {
                aes.Key = GetKeyArray(password);
                aes.Mode = _cipherMode;
                aes.Padding = _paddingMode;
                ICryptoTransform transform = aes.CreateDecryptor();
                byte[] data = null;
                try
                {
                    data = transform.TransformFinalBlock(inputData, 0, inputData.Length);
                }
                catch
                {
                    return null;
                }
                aes.Clear();
                return data;
            }
        }

        /// <summary>
        /// 解密16進制的字符串爲字符串
        /// </summary>
        /// <param name="inputString">要解密的字符串</param>
        /// <param name="password">密碼</param>
        /// <returns>字符串</returns>
        public static string Decrypt(string inputString, string password)
        {
            if (string.IsNullOrWhiteSpace(inputString) || string.IsNullOrWhiteSpace(password))
            {
                return string.Empty;
            }
            byte[] toDecryptArray = ConvertStringToByte(inputString);
            string decryptString = _encoding.GetString(Decrypt(toDecryptArray, password));
            return decryptString;
        }

        /// <summary>
        /// 解密16進制的字符串爲字符串
        /// </summary>
        /// <param name="inputString">須要解密的字符串</param>
        /// <returns>解密後的字符串</returns>
        public static string DecryptString(string inputString)
        {
            if (string.IsNullOrWhiteSpace(_passwd))
            {
                throw new ArgumentException("密鑰不能爲空");
            }
            return Decrypt(inputString, _passwd);
        }
        #endregion
    }

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