文件的对称加密与解密

た入场券 2022-08-27 13:43 161阅读 0赞

<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();
                    }
                }
            }
        }