Qt Cryptographic Architecture: keyloader.cpp

# keyloader.cpp

The code below shows how to load a private key from a PEM format file, including handling any requirement for a passphrase. This is done using the QCA::KeyLoader class.

    /*
     Copyright (C) 2007 Justin Karneges <justin@affinix.com>

     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal
     in the Software without restriction, including without limitation the rights
     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     copies of the Software, and to permit persons to whom the Software is
     furnished to do so, subject to the following conditions:

     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
     AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    */

    // QtCrypto has the declarations for all of QCA
    #include <QtCrypto>

    #include <QCoreApplication>
    #include <QTimer>

    #include <stdio.h>

    class PassphraseHandler: public QObject
    {
            Q_OBJECT
    public:
            QCA::EventHandler handler;

            PassphraseHandler(QObject *parent = 0) : QObject(parent)
            {
                    connect(&handler, SIGNAL(eventReady(int, const QCA::Event &)),
                            SLOT(eh_eventReady(int, const QCA::Event &)));
                    handler.start();
            }

    private slots:
            void eh_eventReady(int id, const QCA::Event &event)
            {
                    if(event.type() == QCA::Event::Password)
                    {
                            QCA::SecureArray pass;
                            QCA::ConsolePrompt prompt;
                            prompt.getHidden("Passphrase");
                            prompt.waitForFinished();
                            pass = prompt.result();
                            handler.submitPassword(id, pass);
                    }
                    else
                            handler.reject(id);
            }
    };

    class App : public QObject
    {
            Q_OBJECT
    public:
            QCA::KeyLoader keyLoader;
            QString str;

            App()
            {
                    connect(&keyLoader, SIGNAL(finished()), SLOT(kl_finished()));
            }

    public slots:
            void start()
            {
                    keyLoader.loadPrivateKeyFromPEMFile(str);
            }

    signals:
            void quit();

    private slots:
            void kl_finished()
            {
                    if(keyLoader.convertResult() == QCA::ConvertGood)
                    {
                            QCA::PrivateKey key = keyLoader.privateKey();
                            printf("Loaded successfully.  Bits: %d\n", key.bitSize());
                    }
                    else
                            printf("Unable to load.\n");

                    emit quit();
            }
    };

    int main(int argc, char **argv)
    {
            QCA::Initializer init;
            QCoreApplication qapp(argc, argv);

            if(argc < 2)
            {
                    printf("usage: keyloader [privatekey.pem]\n");
                    return 0;
            }

            PassphraseHandler passphraseHandler;
            App app;
            app.str = argv[1];
            QObject::connect(&app, SIGNAL(quit()), &qapp, SLOT(quit()));
            QTimer::singleShot(0, &app, SLOT(start()));
            qapp.exec();
            return 0;
    }

    #include "keyloader.moc"