QtAES演算法詳解與應用實例

一、介紹

QtAES是一款基於Qt框架的AES（高級加密標準）演算法的實現工具，在數據傳輸、保護隱私等方面有廣泛的應用。該演算法採用了先進的密碼學設計，可實現128、192和256位的加解密操作，以及ECB、CBC、CFB和OFB等加密模式。

二、核心原理

1、加密原理

AES演算法採用分組密碼機制，對明文塊進行逐塊加密。具體而言，AES將每個明文塊分成16個位元組，然後在4 × 4的矩陣上進行操作。首先對矩陣進行一個初始的變換（AddRoundKey），然後進行9輪操作，每輪都包含四個步驟，分別是SubBytes、ShiftRows、MixColumns和AddRoundKey。最後一輪沒有MixColumns步驟，加密結束後，將密文塊鏈接起來。


void AES::EncryptBlock(unsigned char *Block)
{
    // ...
    for (int i = 0; i < Nb; i++, ptr += 4) {
        for (int n = 0; n < 4; n++) {
            State[n][i] = Block[ptr + n];
        }
    }
    // ...
    AddRoundKey(0);
    // ...
    for (int round = 1; round < Nr; ++round) {
        // ...
        SubBytes();
        ShiftRows();
        MixColumns();
        AddRoundKey(round);
        // ...
    }
    // ...
}

2、解密原理

解密與加密過程類似，只是多了一個逆向操作步驟。即先進行一個AddRoundKey，然後進行9輪的逆向操作，分別是InvSubBytes、InvShiftRows、InvMixColumns和AddRoundKey。最後一輪沒有InvMixColumns，解密結束後，將明文塊鏈接起來。


void AES::DecryptBlock(unsigned char *Block)
{
    // ...
    for (int i = 0; i < Nb; i++, ptr += 4) {
        for (int n = 0; n = 1; --round) {
        // ...
        InvShiftRows();
        InvSubBytes();
        AddRoundKey(round);
        InvMixColumns();
        // ...
    }
    // ...
}

三、安裝與配置

1、安裝

官方提供了源代碼，用戶只需要下載並編譯就能得到QtAES演算法的程序。


$ git clone https://github.com/Lupino/qtaes.git
$ cd qtaes/qtaes/
$ qmake qtaes.pro
$ make

2、配置

用戶可以通過修改源碼中的qtaes_global.h文件來配置演算法加密方式，如打開debug模式、顯示加密過程等。


#define QT_AES_DEBUG
#define QT_AES_NO_QT_NAMESPACE
#define QT_AES_NO_QT_DEBUG_STREAM
#define QT_AES_NO_MEMBER_TEMPLATE_FRIENDS

#define QT_AES_NO_DEBUG_HELPER
#define QT_AES_SEPARATE_QT_RESOURCE_CPP
#define QT_AES_DISABLE_DEPRECATED_BEFORE

四、應用實例

1、文件加密

下面是一個簡單的文件加密程序，實現了對文件的加密和解密操作。


#include <QFile>
#include <QCoreApplication>
#include <QDebug>
#include <qtaes.h>

#define KEY "1234567890123456"

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

    QString fileName = "myfile.txt";
    QFile file(fileName);
    if (!file.open(QIODevice::ReadOnly)) {
        qDebug() << "Failed to open file " << fileName;
        return -1;
    }

    QByteArray data = file.readAll();
    file.close();

    QByteArray key16 = QByteArray(KEY).leftJustified(16);
    QByteArray iv = QByteArray(16, 0);
    QByteArray cipher = QtAES::encrypt(data, key16, iv, QtAES::AES_128, QtAES::CBC);
    qDebug() << "Cipher: " << QString(cipher.toHex());

    QByteArray plain = QtAES::decrypt(cipher, key16, iv, QtAES::AES_128, QtAES::CBC);
    qDebug() << "Plain: " << plain;

    return 0;
}

2、字元串加密

下面是一個將用戶輸入字元串加密的程序，用戶可選擇加密位數及模式。


#include <QCoreApplication>
#include <QDebug>
#include <qtaes.h>

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

    QString text = "Hello World!";
    QByteArray data(text.toUtf8());

    QByteArray key16 = QByteArray("1234567890123456").leftJustified(16);
    QByteArray iv = QByteArray(16, 0);

    QByteArray cipher = QtAES::encrypt(data, key16, iv, QtAES::AES_128, QtAES::CBC);
    qDebug() << "Cipher: " << QString(cipher.toHex());

    QByteArray plain = QtAES::decrypt(cipher, key16, iv, QtAES::AES_128, QtAES::CBC);
    qDebug() << "Plain: " << plain;

    return 0;
}

3、網路傳輸加密

下面是一個使用Qt網路模塊實現的加密網路傳輸程序，服務端將用戶輸入的字元串進行加密後通過TCP發送給客戶端。

服務端：


#include <QObject>
#include <QStringList>
#include <QTcpServer>
#include <QTcpSocket>
#include <qtaes.h>

class Server : public QObject
{
    Q_OBJECT

public:
    explicit Server(QObject *parent = 0)
        : QObject(parent), mServer(new QTcpServer(this))
    {
        connect(mServer, &QTcpServer::newConnection, this, &Server::onNewConnection);
        if (!mServer->listen(QHostAddress::Any, 10000)) {
            qCritical() << mServer->errorString();
            return;
        } else {
            qDebug() << "Server started...";
        }
    }

private slots:
    void onNewConnection()
    {
        QTcpSocket *socket = mServer->nextPendingConnection();
        connect(socket, &QTcpSocket::disconnected, socket, &QTcpSocket::deleteLater);
        connect(socket, &QTcpSocket::readyRead, this, &Server::onReadyRead);
    }

    void onReadyRead()
    {
        QByteArray data = qobject_cast<QTcpSocket*>(sender())->readAll();
        QByteArray key16 = QByteArray("1234567890123456").leftJustified(16);
        QByteArray iv = QByteArray(16, 0);
        QByteArray cipher = QtAES::encrypt(data, key16, iv, QtAES::AES_128, QtAES::CBC);

        qDebug() << "Cipher: " << QString(cipher.toHex());
        qobject_cast<QTcpSocket*>(sender())->write(cipher);
    }

private:
    QTcpServer *mServer;
};

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

    Server server;

    return app.exec();
}

客戶端：


#include <QCoreApplication>
#include <QTcpSocket>
#include <QDebug>
#include <qtaes.h>

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

    QTcpSocket socket;
    socket.connectToHost("127.0.0.1", 10000);
    if (!socket.waitForConnected()) {
        qDebug() << socket.errorString();
        return -1;
    }

    QString text = "Hello World!";
    QByteArray data(text.toUtf8());

    // Encrypt data
    QByteArray key16 = QByteArray("1234567890123456").leftJustified(16);
    QByteArray iv = QByteArray(16, 0);
    QByteArray cipher = QtAES::encrypt(data, key16, iv, QtAES::AES_128, QtAES::CBC);

    qDebug() << "Cipher: " << QString(cipher.toHex());
    // Send encrypted data
    qint64 bytesWritten = socket.write(cipher);
    qDebug() << "Bytes written: " << bytesWritten;
    socket.waitForBytesWritten();

    // Read encrypted data from server
    QByteArray buffer;
    while (socket.waitForReadyRead()) {
        buffer.append(socket.readAll());
    }

    qDebug() << "Received: " << buffer;
    // Decrypt data
    QByteArray plain = QtAES::decrypt(buffer, key16, iv, QtAES::AES_128, QtAES::CBC);

    qDebug() << "Plain: " << plain;

    return 0;
}

原創文章，作者：小藍，如若轉載，請註明出處：https://www.506064.com/zh-tw/n/233954.html