r-zakarya
f245cdcc38
Reported as "Save takes 6 to 8 seconds". A save decrypts the snapshot it just pulled and re-encrypts the patched one - with the same password. That was two full PBKDF2 runs at 600k iterations, four to six seconds each on this phone, for two keys that protect the same file. DecryptContainerEx now hands back the key, its salt and the iteration count, and EncryptContainerWithKey reuses them. The IV is still drawn fresh every time: reusing an IV with the same key breaks GCM entirely, whereas reusing the salt merely yields the same key - which is the whole point. A salt slows an attack on the password; it has no reason to differ between two versions of the same file. EncryptContainer keeps its old shape and now delegates, so there is a single place that composes a container. The log times both halves, so the next measurement says where the remaining seconds are rather than inviting another guess. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
