🐞Bug with encryption

[Fi5t]

I faced a strange bug when tried to work with two instances of this shared preferences. I use Tink as an encryption engine with your library and want to show you some unexcepted behavior when they work together.

P.S. Sorry for the Kotlin :D

        try {
            TinkConfig.register()
        } catch (e: GeneralSecurityException) {
            throw RuntimeException(e)
        }

        val keysetHandle = AndroidKeysetManager.Builder()
            .withSharedPref(this, KEYSET_NAME, PREFERENCE_FILE)
            .withKeyTemplate(AeadKeyTemplates.AES256_GCM)
            .withMasterKeyUri(MASTER_KEY_URI)
            .build()
            .keysetHandle

        val aead = AeadFactory.getPrimitive(keysetHandle)

        val bpInstance1 = BinaryPreferencesBuilder(this)
            .name("main_file")
            .valueEncryption(TinkValueEncryption(aead, "good_data".toByteArray()))
            .build()

        val bpInstance2 = BinaryPreferencesBuilder(this)
            .name("main_file")
            .valueEncryption(TinkValueEncryption(aead, "bad_data".toByteArray()))
            .build()

        bpInstance1.edit {
            putString("my_key", "bug")
        }

        val result = bpInstance2.getString("my_key", "no bug")

I expect to see "GeneralSecurityException" or "no_bug" in the result variable, but I see "bug" there. It's wrong behavior, because I set the different associated data for each instance. Any ideas?

I've prepared a repository to reproduce this bug. Please, check it out and tell me where I was wrong =)

[iamironz]

Hey. Thank you for submitting the bug. This behavior is expected.If you look at the code listing here https://github.com/yandextaxitech/binaryprefs/blob/master/library/src/main/java/com/ironz/binaryprefs/ParametersProvider.java#L17 then you'll see static caching. It's more efficient than using separate cache instances per preference instance. Why do you think this is bug?

[Fi5t]

When the second instance can decrypt data of the first instance despite the fact that both of these instances have different additional data is a bug for me.

[iamironz]

Got it. Lets discuss about in DM