Issue with QCA (Qt C++ Encryption Library) run on windows 7 - c++

Question

I am using Qt 4.8.1, MinGW compiler and Qt Creator, all on windows 7. I want to add an encryption/ decryption library to my project. After searching the web for couple days I found QCA. Fortunately I found a pre-built version using the same C++ compiler I am using, and a pre-built version of the needed plugins.
I followed the instructions to add the QCA library to my project. I used a code like this to encrypt using AES:
QCA::Initializer init = QCA::Initializer();
//Here where the execution stops
QCA::SymmetricKey key = QCA::SymmetricKey(16);
QCA::InitializationVector iv = QCA::InitializationVector(16);
QCA::Cipher cipher = QCA::Cipher(QString("aes128"), QCA::Cipher::CBC,
QCA::Cipher::DefaultPadding, QCA::Encode,
key, iv);
if (!QCA::isSupported("aes128-cbc-pkcs7"))
{
qDebug() << "AES128 is not supported";
return;
}
The code compiles just fine but when I run the application stops with unknown reason.
I really got tired from this bug, if anybody can help it will be very very very appreciated.

Answer 1

For future programmers that might get stuck on this
QCA loads the plugins at runtime, so even if it compiles fine, if the plugin is not in a searchable folder, it won't load.
You can check if that's the problem by calling qDebug() << QCA::supportedFeatures();. If the plugins are not being loaded, you'll get something like:
("random", "md5", "sha1", "keystorelist")
You should be able to see the folders QCA is looking up by calling:
qDebug("%s", QCA::pluginDiagnosticText().toUtf8().constData());
Apparently, plugins must be placed in a subdirectory called crypto in the libs root directory.
You can check for all the paths where Qt looks for libraries using:
qDebug() << QCoreApplication::instance()->libraryPaths();
This documentation might have some useful information: http://doc.qt.io/qt-4.8/qpluginloader.html