Write QCA Encrypt Decrypt to file

[knasan]

Hello everybody,

I would like a file with AES locks, for this I use QCA.
Closing seems to work, but I can not decode it anymore. Everything I've tried so far changes the file slightly (another MD5 comes out) or makes it completely useless.

// code to encrypt and write to file.

 QCA::Initializer init = QCA::Initializer();
    if(QCA::isSupported("aes256-cbc-pkcs7"))
    {
        // input filename
        QTextStream streamin(stdin);
        printf("File: ");
        QString filename = streamin.readLine(0);

        QFile inputFile(filename);
        if(!inputFile.open(QIODevice::ReadOnly))
        {
            qDebug() << "problem while reading ";
            return -1;
        }

        const QByteArray ReadFileByteArray = inputFile.readAll();
        inputFile.close();

        qDebug() << "size of clear file" << ReadFileByteArray.size();

        QCA::SecureArray inputSA = ReadFileByteArray;
        qDebug() << "size of inputSA: " << inputSA.size();

        // Password input
        printf("Password: ");
        QString password = streamin.readLine(0);

        QString ki = password;
        QCA::SymmetricKey key = ki.toUtf8();
        QCA::InitializationVector iv = ki.toUtf8();

        QCA::Cipher cipher(QString("aes256"), QCA::Cipher::CBC, QCA::Cipher::DefaultPadding, QCA::Encode, key, iv);

        QCA::SecureArray encoded = cipher.update(inputSA);
        qDebug() << "size of encoded: " << encoded.size();

        if(!cipher.ok())
        {
            qCritical("update failed");
            return -1;
        }

        cipher.setup(QCA::Encode, key, iv);
        QCA::SecureArray original = cipher.process(encoded);
        qDebug() << "size of original" << original.size();

        if(!cipher.ok())
        {
            qCritical("Final failed");
            return -1;
        }

        QByteArray originaldata = original.toByteArray();
        qDebug() << "size of originaldata: " << originaldata.size();

        QString writeFileName = filename + ".e";

        QFile file1(writeFileName);
        if(!file1.open(QIODevice::WriteOnly))
        {
            qCritical("problem while writing ");
            return -1;
        } else {

            QTextStream streamout(&file1);
            streamout << encoded.toByteArray();
            streamout.flush();
        }
        file1.close();

    } else {
        qDebug() << "no";
        qCritical("aes256-cbc-pkcs7");
    }

    return 0;
}

// code to decrypt

 QCA::Initializer init = QCA::Initializer();
    if(QCA::isSupported("aes256-cbc-pkcs7"))
    {

        printf("File: ");
        QTextStream streamin(stdin);
        QString readFileName = streamin.readLine(0);

        printf("Password: ");
        QString password = streamin.readLine(0);

        QString ki = password;
        QCA::SymmetricKey key = ki.toUtf8();
        QCA::InitializationVector iv = ki.toUtf8();
        QCA::Cipher cipher(QString("aes256"), QCA::Cipher::CBC, QCA::Cipher::DefaultPadding, QCA::Encode, key, iv);

        QFile inputFile(readFileName);
        if(!inputFile.open(QIODevice::ReadOnly))
        {
            qCritical("problem while reading");
            return -1;
        }

        const QByteArray ReadFileByteArray = inputFile.readAll();
        inputFile.close();

        cipher.setup(QCA::Decode, key, iv);
        QCA::SecureArray decoded = cipher.update(ReadFileByteArray);

        if(!cipher.ok())
        {
            qCritical("Final failed");
            return -1;
        }

        // wie kann man das Kennwort überprüfen?

        int cutFile = readFileName.length() -2;

        QFile wFile(readFileName.left(cutFile));
        if(!wFile.open(QIODevice::WriteOnly)) {
            qCritical("problem reading file");
            return -1;
        } else {
            /*QTextStream streamout(&wFile);
            streamout << decoded.;
            streamout.flush();*/

            QByteArray original = decoded.toByteArray();

            QString filename = readFileName.left(cutFile);
            QFile wf(filename);
            wf.open(QIODevice::WriteOnly);
            QDataStream out(&wf);
            out << original;
            wf.close();

            wFile.close();
        }

    } else {
        qDebug() << "no";
        qCritical("aes256-cbc-pkcs7");
    }

    return 0;
}

QDataStream does not work at all.
If I use QTextStream, the file can be opened, but not 100 percent the same. Unfortunately, a file.write (data.toByteArray ()) alters the file so that it does not fit 100 percent anymore.

Does anybody know what I'm doing wrong?

Thank you for your help.

[SGaist]

Hi,

Why not use QFile::write directly rather than the stream operators ?

[knasan]

Thank you. Directly over QFile :: wirite as ByteArray works without problems. Now all I have to do is find out how to check the password. But for this I make another thread on as soon as I can deal with it.