玩轉C#之【Encrypt加密解密】

介紹

• 不可逆加密:原文加密後變成密文，但密文沒辦法解密文回原文
• 可逆加密:原文加密過後的密文，可以在將密文解密回原文
• 對稱:表示加解密是否使用同一個key

MD5 不可逆加密

/// <summary>

    /// 不可逆加密

    /// 1 防止被篡改

    /// 2 防止明文儲存

    /// 3 防止抵赖，數字簽名

    /// </summary>

    public class MD5Encrypt

    {

        #region MD5

        /// <summary>

        /// MD5加密

        /// 使用的UTF8編碼

        /// </summary>

        /// <param name="source">待加密字串</param>

        /// <param name="length">16或32值之一,其他則採用.net默認MD5加密算法</param>

        /// <returns>加密后的字串</returns>

        public static string Encrypt(string source, int length = 32)//默認參數

        {

            if (string.IsNullOrEmpty(source)) return string.Empty;

            HashAlgorithm provider = CryptoConfig.CreateFromName("MD5") as HashAlgorithm;

            byte[] bytes = Encoding.UTF8.GetBytes(source);//這裡需要區別編碼的

            byte[] hashValue = provider.ComputeHash(bytes);

            StringBuilder sb = new StringBuilder();

            switch (length)

            {

                case 16:

                    for (int i = 4; i < 12; i++)

                    {

                        sb.Append(hashValue[i].ToString("x2"));

                    }

                    break;

                case 32:

                    for (int i = 0; i < 16; i++)

                    {

                        sb.Append(hashValue[i].ToString("x2"));

                    }

                    break;

                default:

                    for (int i = 0; i < hashValue.Length; i++)

                    {

                        sb.Append(hashValue[i].ToString("x2"));

                    }

                    break;

            }

            return sb.ToString();

        }

        #endregion MD5



        #region MD5摘要

        /// <summary>

        /// 獲取檔案的MD5摘要

        /// </summary>

        /// <param name="fileName"></param>

        /// <returns></returns>

        public static string AbstractFile(string fileName)

        {

            using (FileStream file = new FileStream(fileName, FileMode.Open))

            {

                return AbstractFile(file);

            }

        }



        /// <summary>

        /// 根據stream獲取檔案摘要

        /// </summary>

        /// <param name="stream"></param>

        /// <returns></returns>

        public static string AbstractFile(Stream stream)

        {

            MD5 md5 = new MD5CryptoServiceProvider();

            byte[] retVal = md5.ComputeHash(stream);



            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < retVal.Length; i++)

            {

                sb.Append(retVal[i].ToString("x2"));

            }

            return sb.ToString();

        }

        #endregion

    }

• 防止程式串改:下載VS安裝文件(md5)從官方網站下載,到非官方網站下載只要確認檔案的md5碼有沒有樣就可以
• 急速秒傳:百度雲 一瞬間就傳完了，第一次上傳，傳完保存MD5，先計算md5--比對-匹配了就不需要上傳了
• GIT/Svn: md5比對

DES 對稱可逆加密

/// <summary>

    /// DES AES Blowfish

    ///  對稱加密算法的優點是速度快，

    ///  缺點是密鑰管理不方便，要求共享密鑰。

    /// 可逆對稱加密，密鑰長度8

    /// </summary>

    public class DesEncrypt

    {

        private static byte[] _rgbKey = ASCIIEncoding.ASCII.GetBytes(Constant.DesKey.Substring(0, 8));

        private static byte[] _rgbIV = ASCIIEncoding.ASCII.GetBytes(Constant.DesKey.Insert(0, "w").Substring(0, 8));



        /// <summary>

        /// DES 加密

        /// </summary>

        /// <param name="text">需要加密的值</param>

        /// <returns>加密后的结果</returns>

        public static string Encrypt(string text)

        {

            DESCryptoServiceProvider dsp = new DESCryptoServiceProvider();

            using (MemoryStream memStream = new MemoryStream())

            {

                CryptoStream crypStream = new CryptoStream(memStream, dsp.CreateEncryptor(_rgbKey, _rgbIV), CryptoStreamMode.Write);

                StreamWriter sWriter = new StreamWriter(crypStream);

                sWriter.Write(text);

                sWriter.Flush();

                crypStream.FlushFinalBlock();

                memStream.Flush();

                return Convert.ToBase64String(memStream.GetBuffer(), 0, (int)memStream.Length);

            }

        }



        /// <summary>

        /// DES解密

        /// </summary>

        /// <param name="encryptText"></param>

        /// <returns>解密后的结果</returns>

        public static string Decrypt(string encryptText)

        {

            DESCryptoServiceProvider dsp = new DESCryptoServiceProvider();

            byte[] buffer = Convert.FromBase64String(encryptText);



            using (MemoryStream memStream = new MemoryStream())

            {

                CryptoStream crypStream = new CryptoStream(memStream, dsp.CreateDecryptor(_rgbKey, _rgbIV), CryptoStreamMode.Write);

                crypStream.Write(buffer, 0, buffer.Length);

                crypStream.FlushFinalBlock();

                return ASCIIEncoding.UTF8.GetString(memStream.ToArray());

            }

        }

    }

RSA 非對稱可逆加密

/// <summary>

    /// RSA ECC

    /// 可逆非對稱加密 

    /// 非對稱加密算法的優點是密鑰管理很方便，缺點速度慢。

    /// </summary>

    public class RsaEncrypt

    {

        /// <summary>

        /// 獲取加密/解密對

        /// 给你一個，是無法推算出另外一个的

        /// 

        /// Encrypt   Decrypt

        /// </summary>

        /// <returns>Encrypt   Decrypt</returns>

        public static KeyValuePair<string, string> GetKeyPair()

        {

            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

            string publicKey = RSA.ToXmlString(false);

            string privateKey = RSA.ToXmlString(true);

            return new KeyValuePair<string, string>(publicKey, privateKey);

        }



        /// <summary>

        /// 加密：内容+加密key

        /// </summary>

        /// <param name="content"></param>

        /// <param name="encryptKey">加密key</param>

        /// <returns></returns>

        public static string Encrypt(string content, string encryptKey)

        {

            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();

            rsa.FromXmlString(encryptKey);

            UnicodeEncoding ByteConverter = new UnicodeEncoding();

            byte[] DataToEncrypt = ByteConverter.GetBytes(content);

            byte[] resultBytes = rsa.Encrypt(DataToEncrypt, false);

            return Convert.ToBase64String(resultBytes);

        }



        /// <summary>

        /// 解密  内容+解密key

        /// </summary>

        /// <param name="content"></param>

        /// <param name="decryptKey">解密key</param>

        /// <returns></returns>

        public static string Decrypt(string content, string decryptKey)

        {

            byte[] dataToDecrypt = Convert.FromBase64String(content);

            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

            RSA.FromXmlString(decryptKey);

            byte[] resultBytes = RSA.Decrypt(dataToDecrypt, false);

            UnicodeEncoding ByteConverter = new UnicodeEncoding();

            return ByteConverter.GetString(resultBytes);

        }





        /// <summary>

        /// 可以合併在一起的，每次產生一组新的密鑰

        /// </summary>

        /// <param name="content"></param>

        /// <param name="encryptKey">加密key</param>

        /// <param name="decryptKey">解密key</param>

        /// <returns>加密后结果</returns>

        private static string Encrypt(string content, out string publicKey, out string privateKey)

        {

            RSACryptoServiceProvider rsaProvider = new RSACryptoServiceProvider();

            publicKey = rsaProvider.ToXmlString(false);

            privateKey = rsaProvider.ToXmlString(true);



            UnicodeEncoding ByteConverter = new UnicodeEncoding();

            byte[] DataToEncrypt = ByteConverter.GetBytes(content);

            byte[] resultBytes = rsaProvider.Encrypt(DataToEncrypt, false);

            return Convert.ToBase64String(resultBytes);

        }

    }

參考資料