AES暗号がピックアップしないIV

Question

暗号化されたテキストが予測できないように、AESでIVを使用しようとしています。ただし、暗号化された16進文字列は常に同じです。

1）マニュアルIV生成

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

2）を生成するために暗号を頼む：

は、私が実際に暗号のinitの呼び出しにいくつかの追加のパラメータを渡すことによって、いくつかのランダム性を追加しようとするいくつかの方法を試してみましたPBEParameterSpec

を使用してIV

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

3）

これらはすべて暗号化されたテキストに影響を与えないようです....ヘルプ!!!

マイコード：

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

私は今、固定秘密鍵を...生成された方法を変更しました。

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; 
    } 

}