Marshmallowで暗号化に失敗しました

Question

SDカードからデータを暗号化して復号化しようとしています。下位バージョンのデバイスで適切なコードを試しましたが、私は1つの例外をmarshmallowで取得しています。

04-19 09:56:50.428: W/System.err(15137): javax.crypto.BadPaddingException: pad block corrupted 
    04-19 09:56:50.432: W/System.err(15137): at com.android.org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher$BufferedGenericBlockCipher.doFinal(BaseBlockCipher.java:1011) 
    04-19 09:56:50.432: W/System.err(15137): at com.android.org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(BaseBlockCipher.java:849) 
    04-19 09:56:50.432: W/System.err(15137): at javax.crypto.Cipher.doFinal(Cipher.java:1502) 
    04-19 09:56:50.432: W/System.err(15137): at com.example.encryptaudio.CryptoFile.decrypt(CryptoFile.java:34) 
    04-19 09:56:50.432: W/System.err(15137): at com.example.encryptaudio.MainActivity$2.onClick(MainActivity.java:116) 
    04-19 09:56:50.432: W/System.err(15137): at android.view.View.performClick(View.java:5201) 
    04-19 09:56:50.432: W/System.err(15137): at android.view.View$PerformClick.run(View.java:21163) 
    04-19 09:56:50.432: W/System.err(15137): at android.os.Handler.handleCallback(Handler.java:746) 
    04-19 09:56:50.432: W/System.err(15137): at android.os.Handler.dispatchMessage(Handler.java:95) 
    04-19 09:56:50.432: W/System.err(15137): at android.os.Looper.loop(Looper.java:148) 
    04-19 09:56:50.432: W/System.err(15137): at android.app.ActivityThread.main(ActivityThread.java:5443) 
    04-19 09:56:50.432: W/System.err(15137): at java.lang.reflect.Method.invoke(Native Method) 
    04-19 09:56:50.432: W/System.err(15137): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 

私は、次の午前のコードは 暗号化され

CryptoFile simpleCrypto = new CryptoFile();     

try { 
    // encrypt audio file send as second argument and corresponding key in first argument. 
     incrept = simpleCrypto.encrypt(KEY, getAudioFile());     

     //Store encrypted file in SD card of your mobile with name vincent.mp3. 

     FileOutputStream fos = new FileOutputStream(new File("/sdcard/vincent.mp3")); 
      fos.write(incrept); 
      fos.close(); 

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

} 

復号

CryptoFile simpleCrypto = new CryptoFile();    

     try { 

    // decrypt the file here first argument is key and second is encrypted file which we get from SD card. 
    decrpt = simpleCrypto.decrypt(KEY, getAudioFileFromSdCard()); 
//play decrypted audio file. 
    playMp3(decrpt);      

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

Crypt.java

public class CryptoFile { 

public byte[] encrypt(String seed, byte[] cleartext) throws Exception {   

     byte[] rawKey = getRawKey(seed.getBytes()); 

    byte[] result = encrypt(rawKey, cleartext); 

    // return toHex(result); 
    return result; 
} 
public byte[] decrypt(String seed, byte[] encrypted) throws Exception { 

    byte[] rawKey = getRawKey(seed.getBytes()); 

    byte[] enc = encrypted; 

    byte[] result = decrypt(rawKey, enc); 

    return result;  } 

//done 
private byte[] getRawKey(byte[] seed) throws Exception { 

    KeyGenerator kgen = KeyGenerator.getInstance("AES"); 

    SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"); 

    sr.setSeed(seed); 

kgen.init(128, sr); // 192 and 256 bits may not be available 

SecretKey skey = kgen.generateKey(); 

byte[] raw = skey.getEncoded(); 

return raw; 
} 
private byte[] encrypt(byte[] raw, byte[] clear) throws Exception { 

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); 

    Cipher cipher = Cipher.getInstance("AES"); 

cipher.init(Cipher.ENCRYPT_MODE, skeySpec); 

byte[] encrypted = cipher.doFinal(clear); 

    return encrypted; 

} 

private byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception { 

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); 

    Cipher cipher = Cipher.getInstance("AES"); 

cipher.init(Cipher.DECRYPT_MODE, skeySpec); 

byte[] decrypted = cipher.doFinal(encrypted); 

    return decrypted; 

} 

} 

Answer 1

AESキーはランダムなデータで構成する必要があります。それらをストリングとして保管すると、情報が失われる可能性が高くなります。 また、暗号化または復号化でエンコードタイプを指定していません。

暗号化

encryptedText = c.doFinal(clearText.getBytes("UTF-8")); 
return Base64.encodeToString(encryptedText, Base64.DEFAULT); 

復号

clearText = c.doFinal(Base64.decode(encryptedText, Base64.DEFAULT)); 
return new String(clearText, "UTF-8");