安卓 - javax.crypto.AEADBadTagException

Question

我目前在尝试解密我已加密的文件时收到 AEADBadTagException。我几乎在 stackoverflow 上到处搜索但找不到解决方案，希望我犯了一个小错误或与编码等有关，因为 GCM 无法验证它生成的标签。

我认为问题出在我尝试加密/解密的文件中。完全相同的代码适用于图像，但是，当我尝试加密 PDF 时，它失败并出现上述错误。

下面的代码没有使用 CipherOutputStream/CipherInputStream，但我已经尝试过，但没有成功。

我知道加密/解密方法不应该这样写，尤其是硬编码的 IV，但现在我只是想让它工作，然后再适本地保护这些方法。

我正在使用 Android KeyStore 获取我的 key 。我知道这部分是有效的，因为我在应用程序中有很多其他的部分使用相同的方法使用 keystore 。另外，此方法适用于图像。

错误发生在 cipher.doFinal(encryptedBytes) 上。当我使用 CipherInputStream 时，它发生在 CipherInputStream(EncryptedFileStream, cipher)

这是代码和错误堆栈，非常感谢任何帮助:

加密

        val fileBytes = inputStream.readBytes()
        val cipher = Cipher.getInstance("AES/GCM/NoPadding")
        keyStoreService.checkKeyAndCreate(ALIAS_FILE_KEY)
        val key = keyStoreService.getFileKey(ALIAS_FILE_KEY)
        val iv = byteArrayOf(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
        cipher.init(Cipher.ENCRYPT_MODE, key, GCMParameterSpec(128, iv))
        val encryptedBytes = cipher.doFinal(fileBytes)
        outputStream = FileOutputStream(file)
        outputStream.write(encryptedBytes)
        outputStream.flush()
        inputStream.close()
        outputStream.close()

解密

    val encryptedFile = File(filePath)
    val encryptedBytes = encryptedFile.readBytes()
    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
    val key = keyStoreService.getFileKey(ALIAS_FILE_KEY)
    val iv = byteArrayOf(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    cipher.init(Cipher.DECRYPT_MODE, key, GCMParameterSpec(128, iv))
    val decryptedBytes = cipher.doFinal(encryptedBytes)

    return ByteArrayInputStream(decryptedBytes)

堆栈跟踪

E/AndroidRuntime: FATAL EXCEPTION: main
Process: onboard.app.passageways, PID: 15441
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:503)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
 Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
 Caused by: javax.crypto.AEADBadTagException
    at android.security.keystore.AndroidKeyStoreCipherSpiBase.engineDoFinal(AndroidKeyStoreCipherSpiBase.java:517)
    at javax.crypto.Cipher.doFinal(Cipher.java:2055)
    at passageways.android.onboard.services.EncryptionService.readEncryptedFile(EncryptionService.kt:79)
    at passageways.android.onboard.fragments.MeetingBookDialogFragment.onViewCreated(Fragment.kt:38)
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1471)
    at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)
    at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:802)
    at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625)
    at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411)
    at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
    at android.os.Handler.handleCallback(Handler.java:873)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:193)
    at android.app.ActivityThread.main(ActivityThread.java:6669)
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
 Caused by: android.security.KeyStoreException: Signature/MAC verification failed
    at android.security.KeyStore.getKeyStoreException(KeyStore.java:839)
    at android.security.keystore.KeyStoreCryptoOperationChunkedStreamer.doFinal(KeyStoreCryptoOperationChunkedStreamer.java:224)
    at android.security.keystore.AndroidKeyStoreAuthenticatedAESCipherSpi$BufferAllOutputUntilDoFinalStreamer.doFinal(AndroidKeyStoreAuthenticatedAESCipherSpi.java:373)
    at android.security.keystore.AndroidKeyStoreCipherSpiBase.engineDoFinal(AndroidKeyStoreCipherSpiBase.java:506)
    at javax.crypto.Cipher.doFinal(Cipher.java:2055) 
    at passageways.android.onboard.services.EncryptionService.readEncryptedFile(EncryptionService.kt:79) 
    at passageways.android.onboard.fragments.MeetingBookDialogFragment.onViewCreated(Fragment.kt:38) 
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1471) 
    at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784) 
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852) 
    at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:802) 
    at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625) 
    at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411) 
    at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366) 
    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273) 
    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:733) 
    at android.os.Handler.handleCallback(Handler.java:873) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:193) 
    at android.app.ActivityThread.main(ActivityThread.java:6669)

Answer 1

事实证明 readBytes() 使用默认的缓冲区大小，并且只返回一个字节缓冲区的长度。所以它实际上并没有以字节为单位返回整个文件，只是达到缓冲区的长度。

我已经切换到使用 CipherOutputStream，请务必在将内容写入标签后包含 flush()!