The read failed with IllegalBlockSizeException and, in logcat, KeymasterUtils status -28. setDigests() authorises the MESSAGE digest only; the MGF1 digest is a separate authorisation whose default is SHA-1 and stays SHA-1 unless setMgf1Digests is called (API 31+). Asking for MGF1-SHA-256 at decrypt time therefore hands the hardware a key that refuses.
Encryption did not complain, because the rebuilt public key is served by the software provider, which accepts any MGF1. So we produced perfectly valid ciphertext that the hardware would not read - the worst shape of bug, since it only surfaces on the next launch. Both sides now pass SHA-256 for the message and SHA-1 for the mask; SHA-1 there weakens nothing, a mask generation function needs no collision resistance.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The prompt raised ActivityNotFoundException: FMX does not show BiometricPrompt from our NativeActivity, it launches its own BiometricFragmentActivity, which lives in fmx.dex.jar but has to be declared in the manifest. Given a translucent framework theme - it hosts the system dialog and draws nothing itself, and the generated resources contain no AppCompat.
Then the read failed and the cache vanished with no trace. LoadVault sorted 'key lost' from 'not authenticated' on the exception message and deleted the file when it guessed the former - so a wrong guess destroyed the cache and the only record of why. It now reports through LastStoreError and deletes nothing; the caller has the log and the context. OpenLocalNow shows the reason, after ShowUnlock rather than before, which was overwriting it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Measured on device: android.security.keystore.UserNotAuthenticatedException on every write. An AES key created with setUserAuthenticationRequired demands a recent authentication to ENCRYPT as well as to decrypt, and the write follows a silent sync with no prompt. The very first write only succeeded because the phone had just been unlocked - a test that passes, then stops passing.
Now an RSA pair: the public half wraps a throwaway AES key with no prompt, the private half - the guarded one - unwraps it. Authentication is required at read time and nowhere else. Two documented traps handled: the public key returned by the Keystore carries the private key's constraints, so it is rebuilt from its encoded form; and that rebuild changes provider, so the OAEP parameters are passed explicitly on both sides - the Keystore defaults MGF1 to SHA-1 where the transformation name suggests SHA-256.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The local vault now opens by itself at launch and the GET runs behind it,
silently. A 304 shows nothing; a network failure shows nothing either -
offline is a normal state, and an alert on every launch only teaches people
to dismiss alerts. Only a new snapshot manifests, by refreshing the list.
That silence is what puts the sync password inside the Keystore-encrypted
file next to the vault: without it a new snapshot cannot be opened, so every
edit made on the desktop would raise a password prompt at launch. The file
already holds every password in plaintext; this one adds almost nothing to
its exposure. A typed password still wins over the stored one, which is how
you fix one that no longer works.
Adopting a snapshot while the app is already open rebuilds the list in place
instead of navigating - mandatory even from the detail screen, since list
rows carry indices into the old vault and a tap would open the wrong entry.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The one-argument overload is load(LoadStoreParameter). Declaring JObject made the bridge look for a method that does not exist - reported at runtime as 'method not found', with nothing at compile time. Same class of mistake as generateSecret earlier: the JNI signature is built from the declared types, so an approximate type is a silent break.
Delphi refuses a second declaration when the first is not marked overload, so the three-argument init was reported as too many parameters. Also adds Androidapi.Jni to silence the non-inlined TJavaArray.Length hints.
My ASCII normalisation had rewritten the sources in LF, which RAD Studio flags on every unit; a .gitattributes rule now pins CRLF for Pascal sources so git does not undo it.
The Keystore key now requires authentication, valid for 30 s afterwards - short enough that an unattended phone is not exploitable, long enough to decrypt and display. Time-bound rather than a per-use CryptoObject: BiometricPrompt's callback would need a Java class compiled into a jar, while FMX already bridges it.
Two aliases, because the auth constraint is fixed when the key is created and cannot be added later. The file header records which key wrote it, so a read knows whether to authenticate first.
A device with neither fingerprint nor lock screen cannot hold such a key, so SaveVault falls back to the plain key rather than giving up the cache. And a failed authentication no longer wipes the cache: the vault is intact, it is the user who cancelled - erasing it would cost a download and 4 s of derivation for a dismissed prompt.
Opening a container costs ~4 s and the iteration count belongs to the desktop format, so the fix is to stop repeating it: derive once per snapshot, then read a local AES file which the hardware accelerates. The key is generated inside the Keystore and never leaves it - the file alone is useless, even rooted.
ETag and vault are encrypted together on purpose: an ETag outliving an unreadable vault would make the server answer 304 with nothing to show. A failed read wipes the cache rather than guessing.
Also normalises every Delphi source to pure ASCII: Delphi reads a BOM-less file as ANSI, so accented comments came back as mojibake, and each PowerShell rewrite added another layer.
r-zakarya