Your books, encrypted and yours
Acronix Books treats your financial data as the sensitive asset it is. It is encrypted at rest, unlocked through a real key-management vault, and never leaves your machine unless you choose to enable cloud sync. We built the security model first, not last.
The threat we design against
A copied database file must reveal nothing
For an offline-first desktop app, the real risks are local: a copied database, a stolen disk, a leaked backup, or edits made outside the app. So the whole file is encrypted, the key is guarded, and every change is chained. Someone who walks off with your file gets ciphertext.
How it works
Defence in depth, on your own machine
Every control below is in the shipping product — not a roadmap promise.
AES-256 encryption at rest
Your entire book lives in a single SQLCipher-encrypted database. Without your key, the file on disk is meaningless bytes — a copied file, stolen disk, or leaked backup reveals nothing.
Envelope key vault
A random 256-bit data key encrypts the database. It is never stored in the clear: a scrypt-derived key-encryption key (KEK, 64 MiB memory-hard) wraps it into per-user key slots.
One-time recovery code
At first run you get a one-time recovery code that wraps the same key. Forget your password and it lets you back in. Lose both, and your data is unrecoverable — by design.
Encrypted login & unlock
Every session is gated by an encrypted unlock. Password hashes live inside the encrypted database; the key is derived only after you authenticate and exists only in memory.
Idle auto-lock
Step away and the book locks itself automatically (15 minutes by default). The data key is zeroed from memory on lock and on quit, so an unattended machine stays protected.
Encrypted backups
A backup is a clean, consistent snapshot written to an .acxb file that stays AES-256 encrypted. It is never a raw copy of a live database, so a backup left on a pen drive or in a cloud folder is as protected as the book itself.
Tamper-evident audit chain
Every privileged action is recorded in a SHA-256 hash chain, where each row commits to the one before it. Out-of-app edits and after-the-fact alterations become detectable.
Role-based access control
Five capability-based roles — Viewer, Operator, Accountant, Admin, and Owner — scope what each user on a shared machine can see and do. Access is checked per capability, not a blanket admin flag.
The screen never touches your data
The part of the app you see cannot reach the database. Every request is validated before it is allowed anywhere near your books, and the interface never holds the encryption key.
Optional cloud sync
Off-site backup, isolated per account
Cloud sync is entirely optional and orthogonal to local unlock — the app runs fully offline with no cloud account at all. When you do turn it on, we hold the security bar high.
TLS in transit, isolated per account
Sync runs over TLS, and every query is scoped to your authenticated account — there is no shared tenancy of your data.
Email-OTP at new-device enrollment
A new device must pass an emailed one-time code before its first full-book pull — right at the moment the access risk appears.
Rate-limited auth with token rotation
Authentication and sync endpoints are rate-limited, and refresh tokens rotate with reuse-detection so a leaked token family is revoked.
Responsible disclosure
Found a security issue? We want to hear from you. Please report it privately to support@acronixbooks.com rather than disclosing it publicly, and give us a reasonable window to investigate and fix it before any public discussion. We will acknowledge your report within 1–2 business days and keep you posted on the fix.