Pourquoi le fichier AES de bureau est-il incompatible avec le fichier AES Android?

Question

J'ai porté une application d'Android sur le bureau qui utilise AES pour crypter certaines données privées. Les deux applications sont capables de chiffrer et de déchiffrer les données pour leur propre usage, mais elles sont incapables de déchiffrer les autres données d'applications. Les clés, IV et algorithmes AES sont identiques. La principale différence entre les deux applications est que l'android-sdk est livré avec le fournisseur de BouncyCastle déjà ajouté à la sécurité alors que l'application de bureau nécessaire

Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); 

application Android:

public class AesFileIo { 
public final static String EOL = "\n"; 
public static final String AES_ALGORITHM = "AES/CTR/NoPadding"; 
public static final String PROVIDER = "BC"; 
private static final SecretKeySpec secretKeySpec = 
    new SecretKeySpec(AES_KEY_128, "AES"); 
private static final IvParameterSpec ivSpec = new IvParameterSpec(IV); 

public String readAesFile(Context c, String fileName) { 
    StringBuilder stringBuilder = new StringBuilder(); 
    try { 
    InputStream is = c.openFileInput(fileName); 
    Cipher cipher = Cipher.getInstance(AES_ALGORITHM, PROVIDER); 
    cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivSpec); 
    CipherInputStream cis = new CipherInputStream(is, cipher); 
    InputStreamReader isr = new InputStreamReader(cis); 
    BufferedReader reader = new BufferedReader(isr); 
    String line; 
    while ((line = reader.readLine()) != null) { 
    stringBuilder.append(line).append(EOL); 
    } 
    is.close(); 
    } catch (java.io.FileNotFoundException e) { 
    // OK, file probably not created yet 
    Log.i(this.getClass().toString(), e.getMessage(), e); 
    } catch (Exception e) { 
    Log.e(this.getClass().toString(), e.getMessage(), e); 
    } 
    return stringBuilder.toString(); 
} 

public void writeAesFile(Context c, String fileName, String theFile) { 
    try { 
    Cipher cipher = Cipher.getInstance(AES_ALGORITHM, PROVIDER); 
    cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivSpec); 
    byte[] encrypted = cipher.doFinal(theFile.getBytes()); 
    OutputStream os = c.openFileOutput(fileName, 0); 
    os.write(encrypted); 
    os.flush(); 
    os.close(); 
    } catch (Exception e) { 
    Log.e(this.getClass().toString(), e.getMessage(), e); 
    } 
} 
} 

application Desktop:

public class AesFileIo { 
    private static final String EOL = "\n"; 
    private static final String AES_ALGORITHM = "AES/CTR/NoPadding"; 
    private static final SecretKeySpec secretKeySpec = 
      new SecretKeySpec(AES_KEY_128, "AES"); 
    private static final IvParameterSpec ivSpec = new IvParameterSpec(IV); 

    public void AesFileIo() { 
     Security.addProvider(new org.bouncycastle.jce.provider 
       .BouncyCastleProvider()); 
    } 

    public String readFile(String fileName) { 
     StringBuilder stringBuilder = new StringBuilder(); 
     try { 
      ObjectInputStream is = new ObjectInputStream(
       new FileInputStream(fileName)); 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM); 
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivSpec); 
      CipherInputStream cis = new CipherInputStream(is, cipher); 
      InputStreamReader isr = new InputStreamReader(cis); 
      BufferedReader reader = new BufferedReader(isr); 
      String line; 
      while ((line = reader.readLine()) != null) { 
       stringBuilder.append(line).append(EOL); 
      } 
      is.close(); 
     } catch (java.io.FileNotFoundException e) { 
      System.out.println("FileNotFoundException: probably OK"); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return stringBuilder.toString(); 
    } 

    public void writeFile(String fileName, String theFile) { 
     try { 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM); 
      cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivSpec); 
      byte[] encrypted = cipher.doFinal(theFile.getBytes()); 
      ObjectOutputStream os = new ObjectOutputStream(
       new FileOutputStream(fileName)); 
      os.write(encrypted); 
      os.flush(); 
      os.close(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 
} 

Answer 1

résolu par

1. Ajout de constructeurs appropriés pour initialiser SecretKeySpec et IvParameterSpec. Se débarrasser de ObjectOutputStream et ObjectInputStream dans l'application de bureau.

application Android:

public class AesFileIo { 
    private static final String EOL = "\n"; 
    private static final String AES_ALGORITHM = "AES/CTR/NoPadding"; 
    private SecretKeySpec secretKeySpec; 
    private IvParameterSpec ivSpec; 
    private static final String PROVIDER = "BC"; 

    AesFileIo(byte[] aesKey, byte[] iv) { 
     ivSpec = new IvParameterSpec(iv); 
     secretKeySpec = new SecretKeySpec(aesKey, "AES"); 
    } 

    public String readFile(Context c, String fileName) { 
     StringBuilder stringBuilder = new StringBuilder(); 
     try { 
      InputStream is = c.openFileInput(fileName); 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM, PROVIDER); 
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivSpec); 
      CipherInputStream cis = new CipherInputStream(is, cipher); 
      InputStreamReader isr = new InputStreamReader(cis); 
      BufferedReader reader = new BufferedReader(isr); 
      String line; 
      while ((line = reader.readLine()) != null) { 
       stringBuilder.append(line).append(EOL); 
      } 
      is.close(); 
     } catch (java.io.FileNotFoundException e) { 
      // OK, file probably not created yet 
      Log.i(this.getClass().toString(), e.getMessage(), e); 
     } catch (Exception e) { 
      Log.e(this.getClass().toString(), e.getMessage(), e); 
     } 
     return stringBuilder.toString(); 
    } 

    public void writeFile(Context c, String fileName, String theFile) { 
     try { 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM, PROVIDER); 
      cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivSpec); 
      byte[] encrypted = cipher.doFinal(theFile.getBytes()); 
      OutputStream os = c.openFileOutput(fileName, 0); 
      os.write(encrypted); 
      os.flush(); 
      os.close(); 
     } catch (Exception e) { 
      Log.e(this.getClass().toString(), e.getMessage(), e); 
     } 
    } 
} 

application Desktop:

public class AesFileIo { 

    private static final String EOL = "\n"; 
    private static final String AES_ALGORITHM = "AES/CTR/NoPadding"; 
    private SecretKeySpec secretKeySpec; 
    private IvParameterSpec ivSpec; 

    AesFileIo(byte[] aesKey, byte[] iv) { 
     Security.addProvider(new org.bouncycastle.jce.provider 
       .BouncyCastleProvider()); 
     ivSpec = new IvParameterSpec(iv); 
     secretKeySpec = new SecretKeySpec(aesKey, "AES"); 
    } 

    public String readFile(String fileName) { 
     StringBuilder stringBuilder = new StringBuilder(); 
     try { 
      FileInputStream fis = new FileInputStream(fileName); 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM); 
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivSpec); 
      CipherInputStream cis = new CipherInputStream(fis, cipher); 
      InputStreamReader isr = new InputStreamReader(cis); 
      BufferedReader reader = new BufferedReader(isr); 
      String line; 
      while ((line = reader.readLine()) != null) { 
       stringBuilder.append(line).append(EOL); 
      } 
      fis.close(); 
     } catch (java.io.FileNotFoundException e) { 
      System.out.println("FileNotFoundException: probably OK"); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return stringBuilder.toString(); 
    } 

    public void writeFile(String fileName, String theFile) { 
     try { 
      Cipher cipher = Cipher.getInstance(AES_ALGORITHM); 
      cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivSpec); 
      byte[] encrypted = cipher.doFinal(theFile.getBytes()); 
      FileOutputStream fos = new FileOutputStream(fileName); 
      fos.write(encrypted); 
      fos.flush(); 
      fos.close(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 
}