Cofferly is a small Windows-friendly Rust desktop app for tracking money held for kids.
Parent PIN screen:
Unlocked wallet ledger:
Cofferly starts with two neutral child wallets. Each wallet keeps a local ledger of deposits and deductions, similar to a handwritten allowance sheet:
- Starting balance
- Money added
- Money spent
- Description for each entry
- Date
- Automatic running balance
- Parent PIN unlock
- Printable ledgers
- Custom child wallet names
- Local encrypted data file
For a local build, the Windows executable is:
target\release\Cofferly.exe
For a portable release zip:
.\scripts\package-windows.ps1 -Version 0.1.0The zip will be created in dist/.
Cofferly opens to a parent PIN screen so kids cannot add, remove, rename, or print entries without a parent unlocking the app first.
The first-run PIN is:
1234
After unlocking, open Settings to choose a different 4-digit PIN.
The PIN is used both to unlock the interface and to derive the key for encrypting the data file on disk. It is a simple family-use protection (4 digits), not high-security encryption.
Cofferly starts with Child 1 and Child 2 so the public app does not include anyone's real names.
After unlocking parent mode, open Settings to rename the selected wallet, update its starting balance, add another child wallet, or delete a wallet. Wallet deletion uses a confirm/cancel step and keeps at least one wallet available.
Use Remove latest entry in Settings to undo the most recent ledger entry for the selected wallet. The app offers a short undo window before the next change.
Use Print this ledger to print the selected child's ledger, or Print both ledgers to print both child wallets together.
Cofferly writes a temporary printable HTML file (in your OS temp folder) and opens it in your browser. Previous print files are cleaned up when the app starts.
The repository includes an Inno Setup script at installer/Cofferly.iss.
Build the release executable first:
cargo build --releaseThen open installer/Cofferly.iss in Inno Setup and compile the installer. The installer output is written to dist/.
Install Rust from rustup.rs, then run:
cargo runTo create a release build:
cargo build --releaseThe app stores data locally in your operating system's app data folder.
Data files are encrypted at rest using the parent PIN (Argon2id key derivation + XChaCha20-Poly1305 authenticated encryption). This protects against casual tampering with the ledger file.
Old plain JSON files (including imports from Atlas Wallet / TallyNest / AirWallet) are automatically migrated to the encrypted format. Legacy files are encrypted on import and the plaintext copies are removed after a verified write. A plain file already at the Cofferly path is re-encrypted on the first successful unlock.
The encryption key is derived once per unlock (envelope encryption); subsequent saves reuse a session data key so the UI does not stall on Argon2id for every transaction. Parent mode also locks automatically after a period of inactivity.
Derived keys and plaintext serialization/decryption buffers are zeroized when dropped. The app's goal is family-use privacy and tamper resistance, not protection against a determined attacker who has the data file and can brute-force all 10,000 PINs offline.
If cargo is not on PATH on Windows, add Rust's Cargo folder to PATH:
$env:Path += ";$env:USERPROFILE\.cargo\bin"
cargo runSee docs/RELEASE.md.
- Simple enough for a family to use without setup
- Local-first, no accounts or cloud service required
- Easy to open source and maintain
- Friendly interface for parents and kids
This is a maintainer-led family app. Contributions are welcome when they fit the project goals, but all changes must go through issues or pull requests and maintainer review.
See CONTRIBUTING.md before opening a pull request.
Repository protection recommendations are documented in docs/GITHUB_SETTINGS.md.
MIT