文件的对称加密与解密

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<pre name="code" class="csharp">    //Encryption,MD5 Hash Algorithm    class MD5Encryption    {        public string GetMd5Hash(string input)        {            using (MD5CryptoServiceProvider md5=new MD5CryptoServiceProvider ())            {                return BitConverter.ToString(md5.ComputeHash                    (UTF8Encoding.Default.GetBytes(input))).Replace("-","");            }        }        public string GetFileMd5Hash(string filePath)        {            using (MD5CryptoServiceProvider md5=new MD5CryptoServiceProvider ())            using (FileStream fs=new FileStream(filePath,FileMode.Open,FileAccess.Read,FileShare.Read))            {                return BitConverter.ToString(md5.ComputeHash(fs)).Replace("-", "");            }        }    }

对称加密

    //Symmetric Algorithm    class SymmetricEncryption    {        static int bufferSize = 128 * 1024;        //salt key        static byte[] salt = { 134, 216, 7, 36, 88, 164, 91, 227, 174, 76, 191, 197, 192, 154, 200, 248 };        static byte[] iv =   { 134, 216, 7, 36, 88, 164, 91, 227, 174, 76, 191, 197, 192, 154, 200, 248 };        private static SymmetricAlgorithm CreateRijndael(string password, byte[] salt)        {            PasswordDeriveBytes pdb = new PasswordDeriveBytes(password, salt, "SHA256", 1000);            SymmetricAlgorithm sma = Rijndael.Create();            sma.KeySize = 256;            sma.Key = pdb.GetBytes(32);            sma.Padding = PaddingMode.PKCS7;            return sma;        }        public static void EncryptFile(string inFile, string outFile, string password)        {            using (FileStream infs=File.OpenRead(inFile),                outfs=File.Open(outFile,FileMode.OpenOrCreate))            using (SymmetricAlgorithm algorithm =CreateRijndael(password,salt))            {                algorithm.IV = iv;                using (CryptoStream crypoStream=new CryptoStream (outfs,algorithm.CreateEncryptor(),CryptoStreamMode.Write))                {                    byte[] bytes = new byte[bufferSize];                    int readSize = -1;                    while ((readSize=infs.Read(bytes,0,bytes.Length))!=0)                    {                        crypoStream.Write(bytes, 0, readSize);                    }                    crypoStream.Flush();                }            }        }        public static void DecryptFile(string inFile, string outFile, string password)        {            using (FileStream infs=File.OpenRead(inFile),                outfs=File.OpenWrite(outFile))            using(SymmetricAlgorithm algorithm=CreateRijndael(password,salt))            {                algorithm.IV = iv;                using (CryptoStream crypoStream=new CryptoStream (infs,algorithm.CreateDecryptor(),CryptoStreamMode.Read))                {                    byte[] bytes = new byte[bufferSize];                    int readSize = -1;                    int numReads = (int)(infs.Length / bufferSize);                    int slack = (int)(infs.Length % bufferSize);                    for (int i = 0; i < numReads; ++i)                    {                        readSize = crypoStream.Read(bytes, 0, bytes.Length);                        outfs.Write(bytes, 0, readSize);                    }                    if (slack>0)                    {                        readSize = crypoStream.Read(bytes, 0, (int)slack);                        outfs.Write(bytes, 0, readSize);                    }                    outfs.Flush();                }            }        }    }

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