encryption final

Author: dhamith93

QuickNote.pro

@@ -31,6 +31,7 @@ SOURCES += \
         src/plaintextedit.cpp \
         src/highlighter.cpp \
         src/database.cpp \
+        src/encryption.cpp \
         src/mdLite/tree.cpp \
         src/mdLite/tokenizer.cpp
 
@@ -39,11 +40,11 @@ HEADERS += \
         src/headers/plaintextedit.h \
         src/headers/highlighter.h \
         src/headers/database.h \
+        src/headers/encryption.h \
         src/mdLite/token.h \
         src/mdLite/tree.h \
         src/mdLite/tokenizer.h
 
-
 FORMS += \
         mainwindow.ui
 
@@ -60,6 +61,9 @@ macx {
     BUNDLE = $$OUT_PWD/$$TARGET$$quote(.app)/Contents
     QMAKE_POST_LINK += ditto \"$$PWD/html/header.html\" \"$$BUNDLE/Resources/\";
     QMAKE_POST_LINK += ditto \"$$PWD/html/footer.html\" \"$$BUNDLE/Resources/\";
+
+    INCLUDEPATH += "/Users/dhamith/Downloads/cryptopp700/"
+    LIBS += "/Users/dhamith/Downloads/cryptopp700/libcryptopp.a"
 }
 
 win32 {

QuickNote.pro.user

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE QtCreatorProject>
-<!-- Written by QtCreator 4.5.2, 2018-08-05T16:10:07. -->
+<!-- Written by QtCreator 4.5.2, 2018-08-14T21:57:30. -->
 <qtcreator>
  <data>
   <variable>EnvironmentId</variable>

mainwindow.ui

@@ -318,8 +318,7 @@ QPushButton:pressed {
            <string notr="true"/>
           </property>
           <property name="plainText">
-           <string># New note
-</string>
+           <string/>
           </property>
          </widget>
         </item>
@@ -377,6 +376,7 @@ QPushButton:pressed {
     <addaction name="actionCopy_selection_as_HTML"/>
     <addaction name="actionExport_HTML"/>
     <addaction name="actionEncrypt_note"/>
+    <addaction name="actionDecrypt_Note"/>
    </widget>
    <addaction name="menuOpen"/>
    <addaction name="menuNote"/>
@@ -423,6 +423,14 @@ QPushButton:pressed {
     <string>Export HTML</string>
    </property>
   </action>
+  <action name="actionDecrypt_Note">
+   <property name="text">
+    <string>Decrypt Note</string>
+   </property>
+   <property name="shortcut">
+    <string>Ctrl+Shift+D</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <customwidgets>

src/encryption.cpp

@@ -0,0 +1,65 @@
+#include "headers/encryption.h"
+#include <QDebug>
+
+using namespace CryptoPP;
+
+std::string Encryption::encrypt(std::string content, std::string passphrase) {
+    AutoSeededRandomPool prng;
+    byte iv[AES::BLOCKSIZE];
+    prng.GenerateBlock(iv, sizeof(iv));
+    std::string ivString(reinterpret_cast< char const* >(iv));
+    SecByteBlock key(AES::MAX_KEYLENGTH+AES::BLOCKSIZE);
+
+    std::string encrypted, output;
+
+    try {
+        HKDF<SHA256> hkdf;
+        hkdf.DeriveKey(key, key.size(), (const byte*) passphrase.data(), passphrase.size(), (const byte*) ivString.c_str(), AES::BLOCKSIZE, NULL, 0);
+
+        CTR_Mode<AES>::Encryption encryption;
+        encryption.SetKeyWithIV(key, AES::MAX_KEYLENGTH, key+AES::MAX_KEYLENGTH);
+
+        StringSource(content, true, new StreamTransformationFilter(encryption, new StringSink(encrypted)));
+
+        std::string finalStr = "encrypted" + ivString + "__ENDIV" + encrypted;
+
+        StringSource(finalStr, true, new Base64Encoder(new StringSink(output)));
+    } catch (const Exception& ex) {
+        qDebug() << ex.what();
+    }
+
+    return  output;
+}
+
+std::string Encryption::decrypt(std::string content, std::string passphrase) {
+    std::string base64Decoded, ivString, decrypted;
+
+    StringSource(content, true, new Base64Decoder(new StringSink(base64Decoded)));
+
+    if (base64Decoded.substr(0, 9) != "encrypted")
+        return "";
+
+    unsigned first = base64Decoded.find("encrypted") + 9; // 9 = encrypted length
+    unsigned last = base64Decoded.find("__ENDIV");
+    ivString = base64Decoded.substr(first, last - first);
+
+    first = base64Decoded.find("__ENDIV") + 7; // 7 = __ENDIV length
+
+    base64Decoded = base64Decoded.substr(first);
+
+    SecByteBlock key(AES::MAX_KEYLENGTH + AES::BLOCKSIZE);
+
+    try {
+        HKDF<SHA256> hkdf;
+        hkdf.DeriveKey(key, key.size(), (const byte*)passphrase.data(), passphrase.size(), (const byte*) ivString.c_str(), AES::BLOCKSIZE, NULL, 0);
+
+        CTR_Mode<AES>::Decryption decryption;
+        decryption.SetKeyWithIV(key, AES::MAX_KEYLENGTH, key + AES::MAX_KEYLENGTH);
+
+        StringSource(base64Decoded, true, new StreamTransformationFilter(decryption, new StringSink(decrypted)));
+    } catch (const Exception& ex) {
+        qDebug() << ex.what();
+    }
+
+    return decrypted;
+}

src/headers/encryption.h

@@ -0,0 +1,21 @@
+#ifndef ENCRYPTION_H
+#define ENCRYPTION_H
+
+#include <string>
+#include "osrng.h"
+#include "cryptlib.h"
+#include "aes.h"
+#include "base64.h"
+#include "sha.h"
+#include "hkdf.h"
+#include "modes.h"
+#include "filters.h"
+
+
+class Encryption {
+    public:
+        static std::string encrypt(std::string content, std::string passphrase);
+        static std::string decrypt(std::string content, std::string passphrase);
+};
+
+#endif // ENCRYPTION_H

src/headers/mainwindow.h

@@ -31,6 +31,10 @@ class MainWindow : public QMainWindow
         void on_actionCopy_selection_as_HTML_triggered();
         void on_actionExport_HTML_triggered();
 
+        void on_actionEncrypt_note_triggered();
+
+        void on_actionDecrypt_Note_triggered();
+
     private:
         Ui::MainWindow *ui;
         Highlighter *highlighter;

src/mainwindow.cpp

@@ -2,6 +2,7 @@
 #include "ui_mainwindow.h"
 #include "headers/database.h"
 #include "headers/highlighter.h"
+#include "headers/encryption.h"
 #include "mdLite/token.h"
 #include "mdLite/tokenizer.h"
 #include <QClipboard>
@@ -10,6 +11,7 @@
 #include <QFileDialog>
 #include <QFileInfo>
 #include <QFontDialog>
+#include <QInputDialog>
 #include <QMessageBox>
 #include <QTextDocumentFragment>
 #include <sstream>
@@ -19,6 +21,8 @@
     #include "headers/macosuihandler.h"
 #endif
 
+QString enc = "";
+
 MainWindow::MainWindow(QWidget *parent) :
                 QMainWindow(parent),
                 ui(new Ui::MainWindow) {
@@ -34,7 +38,7 @@ void MainWindow::init() {
     this->setStyleSheet("QMainWindow { background-color: #505050; border: none; }");
     ui->splitter->setStretchFactor (0,0);
     ui->splitter->setStretchFactor (1,1);
-    ui->noteText->setStyleSheet("QPlainTextEdit { padding: 5% 25% 0 25%; color: white; background-color: #252525; border:none; }");
+    ui->noteText->setStyleSheet("QPlainTextEdit { padding: 5% 5% 0 5%; color: white; background-color: #252525; border:none; }");
     ui->openedNotePath->setStyleSheet("color: white;");
     highlighter = new Highlighter(this);
     highlighter->setDocument(ui->noteText->document());
@@ -252,6 +256,45 @@ void MainWindow::on_actionExport_HTML_triggered() {
     out.close();
 }
 
+void MainWindow::on_actionEncrypt_note_triggered() {
+    QString pswd = QInputDialog::getText(0, "Encrypt Note", "Enter the passphrase...", QLineEdit::Password);
+    std::string input = ui->noteText->toPlainText().toStdString();
+    std::string passphrase = pswd.toStdString();
+
+    if (passphrase.empty())
+        return;
+
+    std::string encryptedText = Encryption::encrypt(input, passphrase);
+
+    if (!encryptedText.empty()) {
+        ui->noteText->setPlainText(QString::fromStdString(encryptedText));
+    } else {
+        QMessageBox msgBox;
+        msgBox.setText("Something went wrong during encryption...");
+        msgBox.exec();
+    }
+
+}
+
+void MainWindow::on_actionDecrypt_Note_triggered() {
+    QString pswd = QInputDialog::getText(0, "Decrypt Note", "Enter the passphrase...", QLineEdit::Password);
+    std::string input = ui->noteText->toPlainText().toStdString();
+    std::string passphrase = pswd.toStdString();
+
+    if (passphrase.empty())
+        return;
+
+    std::string decryptedText = Encryption::decrypt(input, passphrase);
+
+    if (!decryptedText.empty()) {
+        ui->noteText->setPlainText(QString::fromStdString(decryptedText));
+    } else {
+        QMessageBox msgBox;
+        msgBox.setText("It seems like your note is not encrypted...");
+        msgBox.exec();
+    }
+}
+
 void MainWindow::on_fileListOptions_currentTextChanged(const QString &arg1) {
     std::string tag = arg1.toUtf8().constData();
     if (tag == "Recent Notes") {