Encrypt/Decrypt file in QT. How?

bogong

Hello all!
Is there in-box solution in QT for encrypting/decrypting file in Qt? If no what is better to use in QT? I am trying to avoid to use plain C and OpenSSL directly. Is there any library or framework for this issue?

SGaist

Hi,

QCA from the KDE project.

Mucip

Hi,
I use this and liked...

https://wiki.qt.io/Simple_encryption_with_SimpleCrypt

Regards,
Mucip:)

OPit

Hi,
openssl is pretty easy to use :

uchar const KEY_CRYPT[] = "-UKfdjdskf--**fsnx"; // What you want ...
uchar const KEY_IV[] = "Compl3xES3quence"; // What you want ...

#include <openssl/aes.h>
#include <openssl/evp.h>
#include <QFile>

bool decryptOrEncrypt(bool encrypt)
{
    QFile srcFile;
    QFile destFile;

    if(encrypt)
    {
        srcFile.setFileName(m_destinationFile);
        destFile.setFileName(m_encryptedFile);
    }
    else
    {
        srcFile.setFileName(m_encryptedFile);
        destFile.setFileName(m_destinationFile);
    }

    if(!srcFile.open(QIODevice::ReadOnly))
    {
        return false;
    }

    if(!destFile.open(QIODevice::WriteOnly))
    {
        return false;
    }

    const int MAX_BUFFER_SIZE = 1024;
    int out_len;
    EVP_CIPHER_CTX * ctx = EVP_CIPHER_CTX_new();

    EVP_CipherInit(ctx, EVP_aes_128_cbc(), KEY_CRYPT, KEY_IV , encrypt);
    int blocksize = EVP_CIPHER_CTX_block_size(ctx);
    QByteArray cipher_buf;
    cipher_buf.resize(MAX_BUFFER_SIZE + blocksize);

    qint64 size = 0;

    while(!srcFile.atEnd())
    {
        // Read in data in blocks until EOF. Update the ciphering with each read.
        QByteArray inRead = srcFile.read(MAX_BUFFER_SIZE);
        EVP_CipherUpdate(ctx, reinterpret_cast<uchar *>(cipher_buf.data()), &out_len, reinterpret_cast<uchar *>(inRead.data()), inRead.count());
        destFile.write(cipher_buf.data(), out_len);
        size += out_len;
    }

    // Now cipher the final block and write it out.
    EVP_CipherFinal(ctx, reinterpret_cast<uchar *>(cipher_buf.data()), &out_len);
    destFile.write(cipher_buf.data(), out_len);
    size += out_len;
    destFile.close();
    srcFile.close();

    EVP_CIPHER_CTX_free(ctx);

    return true;
}

mrjj

Hi
It should be a really strong coffee before that would look even remotely easy to me..:)
But thank you for the sample.

 EVP_CipherUpdate(ctx, reinterpret_cast<uchar *>(cipher_buf.data()), &out_len, reinterpret_cast<uchar *>(inRead.data()), inRead.count());

bogong

Solution found https://github.com/bricke/Qt-AES Issue closed.