How to calculate hash for a text using QCryptographicHash in Qt

Source Code

Main.cpp

1. include <QtGui/QApplication>
2. include "qmlapplicationviewer.h"
3. include <QCryptographicHash>
4. include "QDeclarativeContext"
5. include "hashcalculate.h"

int main(int argc, char *argv[]) {

   QApplication app(argc, argv);

   HashCalculate*ihashcalc =  new HashCalculate();
   QmlApplicationViewer viewer;
   viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
   QDeclarativeContext *ctxt = viewer.rootContext();
   ctxt->setContextProperty("myContextProperty",ihashcalc);
   viewer.setMainQmlFile(QLatin1String("qml/MD4HashSample/main.qml"));
   viewer.showExpanded();
   return app.exec();

}

hashcalculate.cpp

1. include "hashcalculate.h"
2. include <QCryptographicHash>
3. include "QDebug"

HashCalculate::HashCalculate(QObject *parent) :

   QObject(parent)

{

   iHashValue = "";

}

void HashCalculate::calculateHash(const QString& aOriginalText ) {

QCryptographicHash hash(QCryptographicHash::Md4);
hash.addData(aOriginalText.toUtf8());
SetHash(QString(hash.result().toHex()));
//qDebug() << QString(hash.result().toHex());

}

void HashCalculate::SetHash(const QString& aHashValue) {

iHashValue = aHashValue;

}

QString HashCalculate::getHash() {

return iHashValue;

}

hashcalculate.h

1. ifndef HASHCALCULATE_H
2. define HASHCALCULATE_H

1. include <QObject>

class HashCalculate : public QObject {

   Q_OBJECT

public:

   explicit HashCalculate(QObject *parent = 0);
   Q_INVOKABLE void calculateHash(const QString& aOriginalText );

signals:

public slots:

      QString getHash();
      void SetHash(const QString& aHashValue);

public:

      QString iHashValue;

};

1. endif // HASHCALCULATE_H

Main.qml

import QtQuick 1.0 import com.nokia.symbian 1.0

Window {

   id: window

   StatusBar {
       id: statusBar
       anchors.top: window.top
   }

   PageStack {
       id: pageStack
       anchors { left: parent.left; right: parent.right; top: statusBar.bottom; bottom: toolBar.top }
   }

   ToolBar {
       id: toolBar
       anchors.bottom: window.bottom
       tools: ToolBarLayout {
           id: toolBarLayout
           ToolButton {
               flat: true
               iconSource: "toolbar-back"
               onClicked: pageStack.depth <= 1 ? Qt.quit() : pageStack.pop()
           }
       }
   }

   Component.onCompleted: {
       pageStack.push(Qt.resolvedUrl("MainPage.qml"))
   }

}

MainPage.qml

import QtQuick 1.0 import com.nokia.symbian 1.0

Page {

   id: mainPage

   Text {
       text: qsTr("Enter Text:")
       id:textorg
       color: platformStyle.colorNormalLight
       font.pixelSize: 20
       x:text_originaltxt.x
       y:text_originaltxt.y-45
   }

   Text {
       text: qsTr("MD4 Hash :")
       id: txthshd
       color: platformStyle.colorNormalLight
       font.pixelSize: 20
       x:text_hashedtxt.x
       y:text_hashedtxt.y-40

   }

   TextField {
       id: text_originaltxt
       x: parent.x+5
       y:parent.y+55
       width: parent.width-15
       text : "Nokia"

   }
   TextField {
       id: text_hashedtxt
       x: text_originaltxt.x
       y:text_originaltxt.y+110
       width: parent.width-15
       readOnly: true
       text : ""

   }

   Button {
           id: btnhash
           x:parent.x+50
           y:text_hashedtxt.y+text_hashedtxt.height+txthshd.height+5
           text: "Get Hash"
           onClicked: {
               myContextProperty.calculateHash(text_originaltxt.text)
               text_hashedtxt.text = myContextProperty.getHash()
           }
        }
   Button {
           id: btnclr
           x:parent.x+btnhash.width+130
           y:text_hashedtxt.y+text_hashedtxt.height+txthshd.height+5
           text: "Clear"
           onClicked: {
               text_originaltxt.text = ""
               text_hashedtxt.text = ""
           }
        }

}

About the Update

The implementation has now been converted using the Qt Quick components.As compared with the previous functionality in which a hard-coded text was getting converted into a hash, now the user has flexibility to enter any text & convert it into a hash code as visible in the screenshots.

Source Code

Full source code can be downloaded from here : Media:MD4HashSample.zip

pt:Como criptografar um texto usando QCryptographicHash, em Qt