Nano Vault

An offline, hardware-encrypted personal ledger built specifically for the Ledger Nano X.

Why I wrote this

I wanted an actual useful custom app that I could sideload onto my Ledger Nano X. This is a secure, completely offline vault for tracking personal finances, secret stashes, and emergency reserves. By running this directly on the Ledger's Secure Element, the data is hardware-encrypted and never touches an internet-connected device.

TODO List

• Basic project setup (Rust, no_std, Makefile)
• Set up state management and cryptography skeleton
• Integrate with Ledger SDK and compile to .hex
• Implement on-device UI screens using Ledger's graphics library
• Add APDU handlers for computer/companion app communication
• Implement persistent storage (NVM) to save entries across reboots
• Bind vault encryption securely to the Ledger's 24-word seed phrase

Building

If you have Docker/Orbstack installed, you can build the application using the official Ledger toolchain:

make docker-build

Sideloading & Testing

The Ledger Nano X firmware strictly prohibits sideloading custom, unsigned applications via APDU/developer tools (returning a 0x5120 Instruction Not Supported error). The Custom CA backdoor has been removed from recent Nano X firmware updates.

To test this application, you must use one of the following methods:

1. Speculos Emulator: The official Ledger hardware emulator. It runs locally and provides a virtual display.
2. Physical Nano S Plus: Ledger recommends using a Ledger Nano S Plus for physical hardware testing, as its firmware still supports the developer sideloading backdoor.

Running with Speculos (Docker)

You can run the application locally using the Speculos emulator via Docker. It will host a web interface on port 5001 so you can view and interact with the virtual device.

make docker-build
make emulate