System.Thread

Parallel.ForEach

            ifstream sourceStream(sourceFile.c_str());
            ofstream destStream(destFile.c_str());

            vector<thread> threadPool;

            for (unsigned int i = 0; i < thread::hardware_concurrency(); i++)
            {
                threadPool.emplace_back([&]
                {
                    static mutex sourceMutex, destMutex;
                    bool moreToRead = true;
                    while (moreToRead)
                    {
                        string plain, encrypted;

                        {
                            lock_guard<mutex> io_guard(sourceMutex);
                            moreToRead = (bool)getline(sourceStream, plain);
                        }

                        if (moreToRead)
                        {
                            Encryptor ss(plain, encrypted);

                            {
                                lock_guard<mutex> io_guard(destMutex);
                                destStream << encrypted << endl;
                            }
                        }
                    }
                });
            }

            for (auto &thread : threadPool) thread.join();

0	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
1	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
2	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
3	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
4	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
5	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
6	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
7	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
8	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
9	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668
10	1234567890qwertyuiopasdfghjklzxcvbnm	1522771668