source: comparacioncriptosistemas/rsa/main.cpp

#include <QCoreApplication>

#include <QTime>
#include <QElapsedTimer>
#include <QFile>
#include <QTextStream>

#include <iostream>

#include "crypto++/rsa.h"
#include "crypto++/elgamal.h"
#include "crypto++/osrng.h"
#include <crypto++/files.h>



/**
 * Programa de Cryptopp para realizar estimaciones de ejecuciones del
 * algoritmo RSA
 *
 * https://www.cryptopp.com/wiki/RSA_Cryptography
 *
 *
 * Es necesario instalar los siguientes paquetes:
 * libcrypto++9 y libcrypto++-dev
 *
 */

using namespace CryptoPP;

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    //return a.exec();


    ///////////////////////////////////////
    // Pseudo Random Number Generator
    AutoSeededRandomPool rng;

    ///////////////////////////////////////
    // Generate Parameters
    //InvertibleRSAFunction params;

    //QTime timer;
    QElapsedTimer timer;

    // prefijo del nombre del archivo con el texto a cifrar
    QString messageFile = "message";

    // iterar por el número de archivos (10)
    for (int i = 1; i <= 2; i++)
    {
        messageFile.append(QString::number(i));

        qDebug("generar archivo...");
        // generar registros en archivo de texto
        QString fileName = "registro-rsa-";
        fileName.append(messageFile+"-");
        fileName.append(QDateTime::currentDateTime().toString("dd.MM.yy.hh.mm.ss"));
        fileName.append(".txt");

        messageFile.append(".txt");


        //CryptoPP::FileSource file( qPrintable(messageFile), true, new StringSink( s ) );
        QFile readFile(messageFile);
        assert (readFile.open(QFile::ReadOnly | QFile::Text));
        QTextStream in(&readFile);

        std::string text = in.readAll().toStdString();

        //std::cout << s ;//<< std::endl;
        //std::cout << s.size() << std::endl;

        // archivo de salida de resultados
        QFile registerFile(fileName);
        if (registerFile.open(QFile::WriteOnly))
        {
            // flujo para el archivo de salida de resultados
            QTextStream outFile(&registerFile);


            // linea que mantiene los valores de tiempo
            QString line;

            // iterar 50 veces el proceso de cifrado y descifrado del texto
            for (int j = 0; j < 50; j++)
            {

                qDebug("*************************************************");
                InvertibleRSAFunction params;

                timer.start();
                params.GenerateRandomWithKeySize(rng, 4096);

                int runtime = timer.elapsed(); //gets the runtime in ms
                qDebug(qPrintable("key generation: "+QString::number(runtime)+" ms"));

                line.append(QString::number(runtime));
                line.append(" ");

                ///////////////////////////////////////
                // Create Keys
                RSA::PrivateKey privateKey(params);
                RSA::PublicKey publicKey(params);

                SecByteBlock plaintext( (const unsigned char *) text.data(), text.size() );


                ////////////////////////////////////////////////
                // Encrypt
                RSAES_OAEP_SHA_Encryptor encryptor( publicKey );

                // Now that there is a concrete object, we can validate
                assert( 0 != encryptor.FixedMaxPlaintextLength() );

                //qDebug("encryptor.FixedMaxPlaintextLength(): %zu", encryptor.FixedMaxPlaintextLength());

                // vale la pena leer la siguiente pregunta:
                // https://stackoverflow.com/questions/2033809/im-using-crypto-for-rsa-encryption-my-plain-text-exceeds-fixedmaxplaintextle
                //
                // para RSA mas de 470 bytes hace que el asser que sigue falle
                assert( plaintext.size() <= encryptor.FixedMaxPlaintextLength() );

                // Create cipher text space
                size_t ecl = encryptor.CiphertextLength( plaintext.size() );
                assert( 0 != ecl );
                SecByteBlock ciphertext( ecl );

                timer.start();
                encryptor.Encrypt( rng, plaintext, plaintext.size(), ciphertext );
                runtime = timer.elapsed(); //gets the runtime in ms
                qDebug(qPrintable("RSA encryption time: "+QString::number(runtime)+" ms"));

                line.append(QString::number(runtime));
                line.append(" ");


                ////////////////////////////////////////////////
                // Decrypt
                RSAES_OAEP_SHA_Decryptor decryptor( privateKey );

                // Now that there is a concrete object, we can check sizes
                assert( 0 != decryptor.FixedCiphertextLength() );
                assert( ciphertext.size() <= decryptor.FixedCiphertextLength() );

                // Create recovered text space
                size_t dpl = decryptor.MaxPlaintextLength( ciphertext.size() );
                assert( 0 != dpl );
                SecByteBlock recovered( dpl );

                timer.start();
                DecodingResult result = decryptor.Decrypt( rng, ciphertext, ciphertext.size(), recovered );
                runtime = timer.elapsed(); //gets the runtime in ms
                qDebug(qPrintable("RSA decryption time: "+QString::number(runtime)+" ms"));

                line.append(QString::number(runtime));
                line.append(" ");

                // More sanity checks
                assert( result.isValidCoding );
                assert( result.messageLength <= decryptor.MaxPlaintextLength( ciphertext.size() ) );

                // At this point, we can set the size of the recovered
                //  data. Until decryption occurs (successfully), we
                //  only know its maximum size
                recovered.resize( result.messageLength );

                // SecByteBlock is overloaded for proper results below
                assert( plaintext == recovered );

                std::cout << "Recovered plain text" << std::endl;


                outFile << line << endl;
                line = "";


            }
            messageFile = "message";
        }

    }

    qDebug("salida");
}