Why it fails to decrypt with OpenSSL

[lincoln]

Hi guys, I have the following code, two functions, one to encrypt and the other to decrypt a text string, when encrypting it goes well, but when I want to decrypt, it shows me an empty string, why is this happening? Here I leave the code.

QString MainWindow::encryptPassword(const QString& password) {
  QProcess process;
  QStringList arguments;
  arguments << "enc" << "-aes-256-cbc" << "-a" << "-salt" << "-pass" << "pass:password" << "-in" << "-" << "-out" << "-";
  process.setProgram("openssl");
  process.setArguments(arguments);
  process.start();

  if (!process.waitForStarted()) {
      qDebug() << "Failed to start OpenSSL process.";
      return QString();
    }

  process.write(password.toUtf8());
  process.closeWriteChannel();

  if (!process.waitForFinished()) {
      qDebug() << "Failed to encrypt password with OpenSSL.";
      return QString();
    }

  QString encryptedPassword = process.readAllStandardOutput();
  encryptedPassword.remove('\n');
  return encryptedPassword;
}

QString MainWindow::decryptPassword(const QString& encryptedPassword) {
  QProcess process;
  QStringList arguments;
  arguments << "enc" << "-aes-256-cbc" << "-a" << "-d" << "-salt" << "-pass" << "pass:password" << "-in" << "-" << "-out" << "-";
  process.setProgram("openssl");
  process.setArguments(arguments);
  process.start();

  if (!process.waitForStarted()) {
      qDebug() << "Failed to start OpenSSL process.";
      return QString();
    }

  process.write(encryptedPassword.toUtf8());
  process.closeWriteChannel();

  if (!process.waitForFinished()) {
      qDebug() << "Failed to decrypt password with OpenSSL.";
      return QString();
    }

  QString decryptedPassword = process.readAllStandardOutput();
  decryptedPassword.remove('\n');
  return decryptedPassword;
}

QObject::connect(ui->pushButton, &QPushButton::clicked, this, [&](){
      auto texto = ui->lineEdit->text();
      ui->lineEdit_2->setText(encryptPassword(texto));

    });

QObject::connect(ui->pushButton_2, &QPushButton::clicked, this, [&](){
      auto decrypt = decryptPassword(ui->lineEdit_2->text());
      qInfo() << decrypt;
    });

As you can see in the image, it encrypts the text well, but when decrypting, it shows me an empty string, any suggestion would be appreciated.

[ChrisW67]

@SGaist The encrypt command embedded in the code works as long as openssl is found.

$ echo -n 'sample text' | openssl enc -aes-256-cbc -a -salt -pass pass:password -in - -out - 
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.
U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=

The decrypt command fails if the Base64 encoded, encrypted data is presented without a trailing new line (as it is in the code):

# No newline == fails
$ echo -n 'U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=' | openssl enc -aes-256-cbc -d -a  -salt -pass pass:password -in - -out - 
error reading input file

# Newline == OK
$ echo  'U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=' | openssl enc -aes-256-cbc -d -a  -salt -pass pass:password -in - -out - 
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.
sample text

[SGaist]

Hi,

Might be a silly question but does it work as is on the command line ?

[ChrisW67]

@SGaist The encrypt command embedded in the code works as long as openssl is found.

$ echo -n 'sample text' | openssl enc -aes-256-cbc -a -salt -pass pass:password -in - -out - 
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.
U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=

The decrypt command fails if the Base64 encoded, encrypted data is presented without a trailing new line (as it is in the code):

# No newline == fails
$ echo -n 'U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=' | openssl enc -aes-256-cbc -d -a  -salt -pass pass:password -in - -out - 
error reading input file

# Newline == OK
$ echo  'U2FsdGVkX1/e8CegmWkpiyeZATHB1mn2Au0JRukanMw=' | openssl enc -aes-256-cbc -d -a  -salt -pass pass:password -in - -out - 
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.
sample text

[lincoln]

@ChrisW67 Thanks for your answer, by the way I mention that I was testing the QAESEncryption class, and it also gave me a good result. thanks again for your comment