QT下的Base64加解密

//加密,保存password
QString password = ui->pswLineEdit->text().trimmed();
QByteArray passArray = password.toAscii();
QSqlQuery query;
query.prepare(QString("insert into User(username, password, cardno, usertype) values (:username, :password, :cardno, :usertype)"));
query.addBindValue(userName);
query.addBindValue(passArray.toBase64());
query.addBindValue(cardNo);
query.addBindValue(0);
if(query.exec())
{
//succeed
}

//解密,验证登陆
QString password = ui->pswLineEdit->text().trimmed();
QSqlQuery query;
query.exec(QString("select password from User where username = '%1'").arg(username));
if(!query.isActive())
{
    //查询数据库错误
}
if(!query.next())
{
    //用户名不存在
}
else
{
    QString dataPassword = query.value(0).toString();
    //decrypt
    QByteArray tempArray = QByteArray::fromBase64(dataPassword.toAscii());
    if(password != QString(tempArray))
    //...
}