AES Cipher nicht abholen IV

Question

Ich versuche, eine IV mit AES zu verwenden, so dass der verschlüsselte Text unvorhersehbar ist. Die verschlüsselte Hexadezimal-Zeichenfolge ist jedoch immer gleich.

habe ich versucht, tatsächlich ein paar Methoden versucht eine gewisse Zufälligkeit indem einige zusätzliche Parameter an den Chiffre init Anruf hinzuzufügen:

1) Manuelle IV Generation

byte[] iv = generateIv(); 
IvParameterSpec ivspec = new IvParameterSpec(iv); 

2) cipher Erkundigung zu erzeugen IV

AlgorithmParameters params = cipher.getParameters(); 
params.getParameterSpec(IvParameterSpec.class); 

3) Unter Verwendung eines PBEParameterSpec

byte[] encryptionSalt = generateSalt(); 
PBEParameterSpec pbeParamSpec = new PBEParameterSpec(encryptionSalt, 1000); 

All diese scheinen keinen Einfluss auf den verschlüsselten Text zu haben .... Hilfe !!!

Mein Code:

package com.citc.testencryption; 

import java.security.NoSuchAlgorithmException; 
import java.security.SecureRandom; 

import javax.crypto.Cipher; 
import javax.crypto.SecretKey; 
import javax.crypto.SecretKeyFactory; 
import javax.crypto.spec.IvParameterSpec; 
import javax.crypto.spec.PBEKeySpec; 

import android.app.Activity; 
import android.os.Bundle; 
import android.util.Log; 

public class Main extends Activity { 

public static final int SALT_LENGTH = 20; 
public static final int PBE_ITERATION_COUNT = 1000; 

private static final String RANDOM_ALGORITHM = "SHA1PRNG"; 
private static final String PBE_ALGORITHM = "PBEWithSHA256And256BitAES-CBC-BC"; 
private static final String CIPHER_ALGORITHM = "PBEWithSHA256And256BitAES-CBC-BC"; 

private static final String TAG = Main.class.getSimpleName(); 

@Override 
public void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    try { 

    String password = "password"; 
    String plainText = "plaintext message to be encrypted"; 

    // byte[] salt = generateSalt(); 
    byte[] salt = "dfghjklpoiuytgftgyhj".getBytes(); 
    Log.i(TAG, "Salt: " + salt.length + " " + HexEncoder.toHex(salt)); 
    PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray(), salt, PBE_ITERATION_COUNT); 
    SecretKeyFactory keyFac = SecretKeyFactory.getInstance(PBE_ALGORITHM); 
    SecretKey secretKey = keyFac.generateSecret(pbeKeySpec); 
    byte[] key = secretKey.getEncoded(); 
    Log.i(TAG, "Key: " + HexEncoder.toHex(key)); 

    // PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, ITERATION_COUNT); 

    Cipher encryptionCipher = Cipher.getInstance(CIPHER_ALGORITHM); 

    // byte[] encryptionSalt = generateSalt(); 
    // Log.i(TAG, "Encrypted Salt: " + encryptionSalt.length + " " + HexEncoder.toHex(encryptionSalt)); 
    // PBEParameterSpec pbeParamSpec = new PBEParameterSpec(encryptionSalt, 1000); 
    // byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV(); 
    // Log.i(TAG, encryptionCipher.getParameters() + " "); 
    byte[] iv = generateIv(); 
    IvParameterSpec ivspec = new IvParameterSpec(iv); 

    encryptionCipher.init(Cipher.ENCRYPT_MODE, secretKey, ivspec); 
    byte[] encryptedText = encryptionCipher.doFinal(plainText.getBytes()); 
    Log.i(TAG, "Encrypted: " + HexEncoder.toHex(encryptedText)); // <== Why is this always the same :(

    Cipher decryptionCipher = Cipher.getInstance(CIPHER_ALGORITHM); 
    decryptionCipher.init(Cipher.DECRYPT_MODE, secretKey, ivspec); 
    byte[] decryptedText = decryptionCipher.doFinal(encryptedText); 
    Log.i(TAG, "Decrypted: " + new String(decryptedText)); 

    } catch (Exception e) { 
    e.printStackTrace(); 
    } 

} 

private byte[] generateSalt() throws NoSuchAlgorithmException { 
    SecureRandom random = SecureRandom.getInstance(RANDOM_ALGORITHM); 
    byte[] salt = new byte[SALT_LENGTH]; 
    random.nextBytes(salt); 
    return salt; 
} 

private byte[] generateIv() throws NoSuchAlgorithmException { 
    SecureRandom random = SecureRandom.getInstance(RANDOM_ALGORITHM); 
    byte[] iv = new byte[16]; 
    random.nextBytes(iv); 
    return iv; 
} 

} 

Answer 1

änderte ich die Art, wie ich den geheimen Schlüssel wurde Erzeugung ... nun behoben.

package com.citc.testencryption; 

import java.security.NoSuchAlgorithmException; 
import java.security.SecureRandom; 

import javax.crypto.Cipher; 
import javax.crypto.SecretKey; 
import javax.crypto.SecretKeyFactory; 
import javax.crypto.spec.IvParameterSpec; 
import javax.crypto.spec.PBEKeySpec; 
import javax.crypto.spec.SecretKeySpec; 

import android.app.Activity; 
import android.os.Bundle; 
import android.util.Log; 

public class Main extends Activity { 

    public static final int SALT_LENGTH = 20; 
    public static final int PBE_ITERATION_COUNT = 1000; 

    private static final String RANDOM_ALGORITHM = "SHA1PRNG"; 
    private static final String PBE_ALGORITHM = "PBEWithSHA256And256BitAES-CBC-BC"; 
    private static final String CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding"; 

    private static final String TAG = Main.class.getSimpleName(); 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     try { 

      String password = "password"; 
      String plainText = "plaintext message to be encrypted"; 

      // byte[] salt = generateSalt(); 
      byte[] salt = "dfghjklpoiuytgftgyhj".getBytes(); 
      Log.i(TAG, "Salt: " + salt.length + " " + HexEncoder.toHex(salt)); 
      PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray(), salt, PBE_ITERATION_COUNT, 256); 
      SecretKeyFactory factory = SecretKeyFactory.getInstance(PBE_ALGORITHM); 
      SecretKey tmp = factory.generateSecret(pbeKeySpec); 
      SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES"); 
      byte[] key = secret.getEncoded(); 
      Log.i(TAG, "Key: " + HexEncoder.toHex(key)); 

      // PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, ITERATION_COUNT); 

      Cipher encryptionCipher = Cipher.getInstance(CIPHER_ALGORITHM); 

      // byte[] encryptionSalt = generateSalt(); 
      // Log.i(TAG, "Encrypted Salt: " + encryptionSalt.length + " " + HexEncoder.toHex(encryptionSalt)); 
      // PBEParameterSpec pbeParamSpec = new PBEParameterSpec(encryptionSalt, 1000); 
      // byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV(); 
      Log.i(TAG, encryptionCipher.getParameters() + " "); 
      byte[] iv = generateIv(); 
      IvParameterSpec ivspec = new IvParameterSpec(iv); 

      encryptionCipher.init(Cipher.ENCRYPT_MODE, secret, ivspec); 
      byte[] encryptedText = encryptionCipher.doFinal(plainText.getBytes()); 
      Log.i(TAG, "Encrypted: " + HexEncoder.toHex(encryptedText)); 

      Cipher decryptionCipher = Cipher.getInstance(CIPHER_ALGORITHM); 
      decryptionCipher.init(Cipher.DECRYPT_MODE, secret, ivspec); 
      byte[] decryptedText = decryptionCipher.doFinal(encryptedText); 
      Log.i(TAG, "Decrypted: " + new String(decryptedText)); 

     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

    } 

    private byte[] generateSalt() throws NoSuchAlgorithmException { 
     SecureRandom random = SecureRandom.getInstance(RANDOM_ALGORITHM); 
     byte[] salt = new byte[SALT_LENGTH]; 
     random.nextBytes(salt); 
     return salt; 
    } 

    private byte[] generateIv() throws NoSuchAlgorithmException { 
     SecureRandom random = SecureRandom.getInstance(RANDOM_ALGORITHM); 
     byte[] iv = new byte[16]; 
     random.nextBytes(iv); 
     return iv; 
    } 

}