Behaviour of sqleet library if call to entropy function fails about sqleet

[resilar]

I agree that the current behavior is non-ideal. A better approach is to return an error and prevent accessing encrypted databases if entropy generation fails. Maybe also spam error messages to stderr given the critical security implications of the failure. In practice, entropy generation should never be broken except maybe on emulators or early in the boot of embedded systems.

In my opinion, the best solution would be to avoid pseudorandom number generation altogether by switching to deterministic nonces based on counters or hashes. However, maintaining persistent counter(s) in a simple and efficient way is an unsolved problem in the context of SQLite3 encryption extensions. Hashing the plaintext contents of a database page incurs a small performance hit but would be easy to implement. Replacing the hash algorithm with keyed BLAKE2 (or other HMAC) would be nice as the result could serve as a MAC and nonce for ChaCha20 at the same time (allowing removal of Poly1305, but that would break compatibility).

Anyway, I will modify the code to return errors on failing entropy generation. And maybe consider the fancy HMAC nonces for the next major version of sqleet (if there ever will be one).