Ich verwende Crypto ++, um Geschwindigkeitstests für Verschlüsselungsalgorithmen durchzuführen. Ich versuche mal, wie lange es dauert, die Daten zu verschlüsseln, dann zu entschlüsseln (eventuell mit mehr Dateigrößen und anderen Algorithmen). Ich stoße auf ein Problem, bei dem ich den Code nicht durchlaufen kann. Im folgenden Code verwende ich Blowfish, aber wenn ich zum Verschlüsselungsteil komme, erhalte ich den Fehler:

HashVerificationFilter: message hash or MAC not valid

Was kann ich tun, um das zu beheben? Muss ich es in eine Funktion setzen? Wenn ja, wie würde ich das machen?

/**
 * g++ encryption_tests.cpp -o encryption_tests -lcryptopp -lpthread -L.
 */
#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <ctime>


#include "cryptoplusplus/osrng.h"
using CryptoPP::AutoSeededRandomPool;

#include "cryptoplusplus/cryptlib.h"
using CryptoPP::Exception;

#include "cryptoplusplus/hex.h"
using CryptoPP::HexEncoder;
using CryptoPP::HexDecoder;

#include "cryptoplusplus/modes.h"
#include "cryptoplusplus/aes.h"

#include "cryptoplusplus/filters.h"
using CryptoPP::StringSink;
using CryptoPP::StringSource;
using CryptoPP::AuthenticatedEncryptionFilter;
using CryptoPP::AuthenticatedDecryptionFilter;
using namespace std;

#include "cryptoplusplus/filters.h"
using CryptoPP::StringSink;
using CryptoPP::StringSource;
using CryptoPP::AuthenticatedEncryptionFilter;
using CryptoPP::AuthenticatedDecryptionFilter;

#include "cryptoplusplus/blowfish.h"
using CryptoPP::Blowfish;

#include "crypto++/eax.h"
using CryptoPP::EAX;

#include "cryptoplusplus/secblock.h"
using CryptoPP::SecByteBlock;

int main( int argc, char* argv[] ) {
    // Declaring variables
    const int NUMBER_OF_RUNS = 3;
    const int NUMBER_OF_TXT_FILES = 9;
    const int NUMBER_OF_JPG_FILES = 6;
    const int NUMBER_OF_PNG_FILES = 6;
    const int NUMBER_OF_AVI_FILES = 2;

    string file_names_txt[NUMBER_OF_TXT_FILES] = { "10B.txt", "100B.txt", "1KB.txt", "10KB.txt", "100KB.txt", "1MB.txt", "5MB.txt", "10MB.txt", "20MB.txt" };
    string file_names_jpg[NUMBER_OF_JPG_FILES] = { "1KB.jpg", "10KB.jpg", "100KB.jpg", "1MB.jpg", "3MB.jpg", "5MB.jpg" };
    string file_names_png[NUMBER_OF_PNG_FILES] = { "100B.png", "500B.png","1KB.png", "10KB.png","1MB.png", "5MB.png" };
    string file_names_avi[NUMBER_OF_AVI_FILES] = { "4MB.avi", "10MB.avi" };

    int time_data [NUMBER_OF_RUNS];
    string plaintext, cipher, encoded, recovered, sample_files_path, data_file, line_contents; 
    string initial_cpp_time_data = "";
    clock_t time_start, time_stop;
    double run_time, time_difference, time_average = 0;

    // This loop will run the test NUMBER_OF_RUNS times
    for ( int i = 0 ; i < NUMBER_OF_RUNS ; i++ ) {
        time_start = clock();

    // This class seeds itself using an operating system provided RNG
    AutoSeededRandomPool prng;
    // Generate a random key
    SecByteBlock key(Blowfish::DEFAULT_KEYLENGTH);
    prng.GenerateBlock(key, key.size());
    // Generate a random initialization vector
    byte iv[Blowfish::BLOCKSIZE];
    prng.GenerateBlock(iv, sizeof(iv));
    // Set key width
    EAX< Blowfish >::Encryption e;
    e.SetKeyWithIV(key, key.size(), iv);

    // Grab the data from the file we want to run the test on
    sample_files_path = "sample_files/" + file_names_txt[8];
    ifstream initial_file_contents ( sample_files_path.c_str() );
    if (initial_file_contents.is_open()) {
        while ( getline( initial_file_contents, line_contents ) ) {
            plaintext = plaintext + line_contents;
            plaintext.push_back('\n');
            initial_file_contents.close();
        }
    } else {
        cout << "Unable to open file" << endl;
    }

    // Encrypts the plaintext
    try {
        StringSource(plaintext, true, new AuthenticatedEncryptionFilter(e, new StringSink(cipher) ) ); 
    } catch ( const CryptoPP::Exception& e ) {
        cerr << e.what() << endl;
        exit(1);
    }


        // Decrypts the test
        try {
            EAX< Blowfish >::Decryption d;
            d.SetKeyWithIV(key, key.size(), iv);
            StringSource s(cipher, true, new AuthenticatedDecryptionFilter( d, new StringSink(recovered) ) );
        } catch ( const CryptoPP::Exception& e ) {
            cerr << e.what() << endl;
            exit(1);
        }

        // Stop the clock, calculate the time difference, turn to milliseconds
        time_stop = clock();
        time_difference = time_stop - time_start;
        run_time = time_difference / ( CLOCKS_PER_SEC / 1000 );
        time_data[i] = run_time;
        cout << "time_data[" << i << "]: " << time_data[i] << " milliseconds" << endl;
    }

    //Grab the data from the old file
    ifstream initial_cpp_time_data_file ( "cpp_time_data.txt" );
    if (initial_cpp_time_data_file.is_open()) {
        while ( getline( initial_cpp_time_data_file, line_contents ) ) {
            initial_cpp_time_data = initial_cpp_time_data + line_contents;
            initial_cpp_time_data.push_back('\n');
        }
            initial_cpp_time_data_file.close();
    } else {
        initial_cpp_time_data = "";
    }

    // Created a new file
    ofstream time_data_file;
    time_data_file.open("cpp_time_data.txt");

    // Insert old data first
    time_data_file << initial_cpp_time_data << endl;

    // Show the file the test ran on and insert the new data
    time_data_file << sample_files_path << endl;
    for ( int i = 0 ; i < NUMBER_OF_RUNS ; i++ ) {
        time_data_file << "time_data[" << i << "]: " << time_data[i] << " milliseconds" << endl;
        time_average = time_average + time_data[i];
    }
    time_average = time_average / NUMBER_OF_RUNS;
    time_data_file << "The average time for this is " << time_average << " milliseconds" << endl;
    cout << "The average time for this is " << time_average << " milliseconds" << endl;
    time_data_file.close();
    cout << "Done!\n";

    return 0;
}