(IllegalBlockSizeException) Eingabe Länge muss mehrere 16 sein, wenn mit gepolsterten Chiffre entschlüsseln

Question

Ich arbeite derzeit an einem Sommer-Projekt, das eine Datei mit AES verschlüsselt oder entschlüsselt. Wenn ich jedoch denselben Schlüssel verwende, der zum Verschlüsseln von Objekten verwendet wird, erhalte ich beim Entschlüsseln eine unzulässige Blockgrößenausnahme. Ich bin sehr neu in der Kryptographie, aber ein ziemlich erfahrener Java-Programmierer.

Entcodert Klasse:

package com.spencergang.fem; 

import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.security.InvalidKeyException; 
import java.security.Key; 
import java.security.NoSuchAlgorithmException; 

import javax.crypto.BadPaddingException; 
import javax.crypto.Cipher; 
import javax.crypto.IllegalBlockSizeException; 
import javax.crypto.NoSuchPaddingException; 
import javax.crypto.spec.SecretKeySpec; 

public class Cryptographer { 
    private static final String ALGORITHM = "AES"; 
    private static final String TRANSFORMATION = "AES"; 

    //Method for cryptography 
    public static void crypto(int cipherMode, String key, File inputFile, File outputFile) throws CryptoException { 
     try{ 
      Key secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM); 
      Cipher cipher = Cipher.getInstance(TRANSFORMATION); 
      cipher.init(cipherMode, secretKey); 

      FileInputStream inputStream = new FileInputStream(inputFile); 
      byte[] inputBytes = new byte[(int) inputFile.length()]; 
      inputStream.read(inputBytes); 

      byte[] outputBytes = cipher.doFinal(inputBytes); 

      FileOutputStream outputStream = new FileOutputStream(outputFile); 
      outputStream.write(outputBytes); 

      inputStream.close(); 
      outputStream.close(); 
     }catch(NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | BadPaddingException | IllegalBlockSizeException | IOException ex){ 
      throw new CryptoException("ERROR ENCRYPTING/DECRYPTING FILE", ex); 
     } 
    } 

    //Encryption 
    public static void encrypt(String key, File inputFile, File outputFile) throws CryptoException { 
     crypto(Cipher.ENCRYPT_MODE, key, inputFile, outputFile); 
    } 

    //Decryption 
    public static void decrypt(String key, File inputFile, File outputFile) throws CryptoException { 
     crypto(Cipher.DECRYPT_MODE, key, inputFile, outputFile); 
    } 
} 

Crypto Klasse:

package com.spencergang.fem; 

public class CryptoException extends Exception { 
    public CryptoException(){ 
    } 

    public CryptoException(String message, Throwable throwable){ 
     super(message, throwable); 
    } 
} 

Und schließlich meine Controller-Klasse, mit FXML Ich habe eine sehr schöne GUI erstellt:

package com.spencergang.fem; 

import java.io.File; 

import javafx.fxml.FXML; 
import javafx.scene.control.Alert; 
import javafx.scene.control.Alert.AlertType; 
import javafx.scene.control.Button; 
import javafx.scene.control.CheckBox; 
import javafx.scene.control.TextField; 
import javafx.stage.FileChooser; 

public class Controller { 
    @FXML 
    private TextField path; 
    @FXML 
    private TextField destination; 
    @FXML 
    private TextField key; 
    @FXML 
    private CheckBox encryption; 
    @FXML 
    private CheckBox decryption; 
    @FXML 
    private Button begin; 
    @FXML 
    private Button browse; 

    private MainApp mainApp; 

    private Cryptographer crypto; 

    String selectedKey; 
    File input; 
    File output; 
    String filePath; 
    String fileName; 
    String destinationPath; 
    String destinationFile; 
    String finalDestinationPath; 

    //Default Constructor; 
    public Controller(){ 
    } 

    @FXML 
    private void initalize(){ 
    } 

    public void setMainApp(MainApp mainApp){ 
     this.mainApp = mainApp; 
    } 

//////////////////////////////////////////////////////////////////////////////////////////// 
//////////////////////ENCRYPTION AND DECRYPTION METHODS///////////////////////////////////// 
//////////////////////////////////////////////////////////////////////////////////////////// 

    private void handleEncryption(String key, File inputFile, File outputFile) throws CryptoException{ 
     crypto.encrypt(key, inputFile, outputFile); 
    } 

    private void handleDecryption(String key, File inputFile, File outputFile) throws CryptoException{ 
     crypto.decrypt(key, inputFile, outputFile); 
    } 

//////////////////////////////////////////////////////////////////////////////////////////// 
//////////////////////BUTTON HANDLER METHODS//////////////////////////////////////////////// 
////////////////////////////////////////////////////////////////////////////////////////////  

    @FXML 
    private void handleBegin() throws CryptoException{ 

     if(!(destination.getText().trim().isEmpty() || destination.getText() == "" || destination.getText() == null)){ 
      finalDestinationPath = destinationPath + destination.getText(); 
      output = new File(finalDestinationPath); 
     } 

     if(checkFields() == true){ 
      selectedKey = key.getText(); 
     }else{ 
      fieldAlert(); 
     } 

     if(checkBoxes() == 1){ 
      handleEncryption(selectedKey, input, output); 
     }else if(checkBoxes() == 2){ 
      handleDecryption(selectedKey, input, output); 
     }else if(checkBoxes() == 3){ 
      doubleCheckAlert(); 
     }else if(checkBoxes() == 4){ 
      noCheckAlert(); 
     } 
    } 

    @FXML 
    private void handleBrowse(){ 
     FileChooser fileChooser = new FileChooser(); 
     File file; 
     fileChooser.setTitle("Select File"); 
     file = fileChooser.showOpenDialog(mainApp.getPrimaryStage()); 
     filePath = file.getAbsolutePath(); 
     fileName = file.getName(); 
     System.out.println(fileName); 
     path.setText(filePath); 
     destinationPath = filePath.replace(fileName, ""); 
     input = file; 
    } 

//////////////////////////////////////////////////////////////////////////////////////////// 
//////////////////////HELPER METHODS//////////////////////////////////////////////////////// 
//////////////////////////////////////////////////////////////////////////////////////////// 

    private boolean checkFields(){ 
     if(path.getText().trim().isEmpty() || destination.getText().trim().isEmpty() || key.getText().trim().isEmpty() || destination.getText() == "" || key.getText() == "" || path.getText() == null || destination.getText() == null || key.getText() == null){ 
      return false; 
     }else{ 
      return true; 
     } 
    } 

    private int checkBoxes(){ 
     if(encryption.isSelected() && decryption.isSelected()){ 
      return 3; 
     }else if(decryption.isSelected()){ 
      return 2; 
     }else if(encryption.isSelected()){ 
      return 1; 
     }else{ 
      return 4; 
     } 
    } 

//////////////////////////////////////////////////////////////////////////////////////////// 
//////////////////////ERROR AND CONFIRMATION ALERTS///////////////////////////////////////// 
//////////////////////////////////////////////////////////////////////////////////////////// 

    private void encryptionAlert(){ 
     Alert alert = new Alert(AlertType.CONFIRMATION); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("Encryption Successful"); 
     alert.setHeaderText("File Encrypted"); 
     alert.setContentText("Your file has been successfully encrypted!"); 
     alert.showAndWait(); 
    } 

    private void fieldAlert(){ 
     Alert alert = new Alert(AlertType.CONFIRMATION); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("ERROR"); 
     alert.setHeaderText("Empty Field(s)"); 
     alert.setContentText("Check that you have filled out all fields"); 
     alert.showAndWait(); 
    } 

    private void decryptionAlert(){ 
     Alert alert = new Alert(AlertType.CONFIRMATION); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("Decryption Successful"); 
     alert.setHeaderText("File Decrypted"); 
     alert.setContentText("Your file has been successfully decrypted!"); 
     alert.showAndWait(); 
    } 

    private void failureAlert(){ 
     Alert alert = new Alert(AlertType.ERROR); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("ERROR"); 
     alert.setHeaderText("File Not Found"); 
     alert.setContentText("Please check your path values"); 
     alert.showAndWait(); 
    } 

    private void doubleCheckAlert(){ 
     Alert alert = new Alert(AlertType.ERROR); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("ERROR"); 
     alert.setHeaderText("Selection Error"); 
     alert.setContentText("Please select only one option"); 
     alert.showAndWait(); 
    } 

    private void noCheckAlert(){ 
     Alert alert = new Alert(AlertType.ERROR); 
     alert.initOwner(mainApp.getPrimaryStage()); 
     alert.setTitle("ERROR"); 
     alert.setHeaderText("Selection Error"); 
     alert.setContentText("Please select an option"); 
     alert.showAndWait(); 
    } 
} 

Fehlermeldung :

Caused by: javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher 
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:913) 
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:824) 
    at com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:436) 
    at javax.crypto.Cipher.doFinal(Cipher.java:2165) 
    at com.spencergang.fem.Cryptographer.crypto(Cryptographer.java:32) 
    ... 61 more 

Dies ist nicht für Klasse in irgendeiner Weise, nur ein Sommer-Projekt, um mich beschäftigt und frisch zu halten. Bitte helfen Sie!

Answer 1

Verschlüsseln Sie die Daten, dann , ohne es in eine Datei zu schreiben, entschlüsseln Sie die Bytes sofort. Funktioniert es? Oder lesen Sie die Bytes unmittelbar nach dem Schreiben und vergleichen Sie sie mit dem Original. Passen sie zusammen? Das Problem könnte darin bestehen, dass Ihr FileOutputStream die Bytes in die Datei in einer Zeichenkodierung anstatt in eine Binärdatei schreibt. In diesem Fall könnten illegale Sequenzen (in dieser gegebenen Kodierung) auf dem Weg zur Datei modifiziert werden, wodurch Ihr Geheimtext unerwartet geändert wird.