How to calculate hash for a text using QCryptographicHash in Qt

This code snippet shows how to calculate hash for a text string using QCryptographicHash.

This article needs to be updated: If you found this article useful, please fix the problems below then delete the {{ArticleNeedsUpdate}} template from the article to remove this warning.

Reasons: hamishwillee (09 Feb 2012)
Needs to remove the QWidget based UI components of this article as Qt Quick is now recommened.

Article Metadata

---

Tested with

SDK: Qt SDK 1.1.3

Devices(s): Nokia C5-00S60, Emulator, Simulator

---

Compatibility

Platform(s): S60 3rd Edition FP1, S60 3rd Edition FP2, S60 5th Edition, Symbian^3, Qt 4.6, Qt 4.7

Device(s): All which support Qt

---

Article

Keywords: QCryptographicHash

Created: mind_freak (10 Apr 2009)

Reviewed: NegInfinity (15 Sep 2011)

Last edited: hamishwillee (15 Feb 2012)

Some Related Function

• Adds the data to the cryptographic hash:

QByteArray string = "Nokia";
QCryptographicHash hasher(QCryptographicHash::Sha1);
hasher.addData(string);

• Returns the final hash value.

QByteArray string1=hasher.result();

Source Code

Main.cpp

#include <QtGui/QApplication>
#include <QWidget>
#include <QHBoxLayout>
#include <QCryptographicHash>
#include <QString>
#include <QByteArray>
#include <QLineEdit>
#include <QLabel>
#include <QGridLayout>
#include <QPushButton>
#include <QHBoxLayout>
 
int main(int argc, char **argv){
	QApplication app(argc, argv);
 
	QWidget mainWindow;
	QGridLayout* layout=new QGridLayout();
 
	//widget initialization
	QLineEdit *hashTextEdit=new QLineEdit(),
		*originalTextEdit = new QLineEdit();
	originalTextEdit->setReadOnly(true);
	originalTextEdit->setText(QObject::tr("Nokia"));
	hashTextEdit->setReadOnly(true);
	QLabel *hashLabel=new QLabel(QObject::tr("MD4 &Hash:")),
		*originalTextLabel = new QLabel(QObject::tr("Original &Text:"));
	hashLabel->setBuddy(hashTextEdit);
	originalTextLabel->setBuddy(originalTextEdit);
 
	//widget placement
	layout->addWidget(originalTextLabel, 0, 0);
	layout->addWidget(originalTextEdit, 0, 1);
	layout->addWidget(hashLabel, 1, 0);
	layout->addWidget(hashTextEdit, 1, 1);
 
	//bottom layout initialization ("close" button)
	QHBoxLayout* bottomLayout = new QHBoxLayout();
	bottomLayout->addStretch();
	QPushButton* closeButton = new QPushButton(QObject::tr("C&lose"));
	bottomLayout->addWidget(closeButton);
	bottomLayout->addStretch();
	bottomLayout->setMargin(0);
 
	layout->addLayout(bottomLayout, 2, 0, 1, 2);
 
	QObject::connect(closeButton, SIGNAL(clicked()), &mainWindow, SLOT(close()));
 
	mainWindow.setLayout(layout);
 
	//actual hash calculation TODO: make proper widget with signal/slots for hash calculation
	QCryptographicHash hash(QCryptographicHash::Md4);
	hash.addData(originalTextEdit->text().toUtf8());
	hashTextEdit->setText(QString(hash.result().toHex()));
 
	mainWindow.showMaximized();
 
	return app.exec();
}

ScreenShot