August 16, 2026solanahardware-walletsecurityrustair-gapbuildersfaraday

Faraday: open-source air-gapped Solana hardware signer

Technical guide to Faraday (faraday.to) — air-gapped Solana signer suite: Pi Zero / ESP32 firmware, RAM-only keys, QR I/O, browser extension (Wallet Standard), Seeker mobile. Repo Faraday-signer/faraday. Build simulator, security model, when to use.

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Faraday (faraday.to) is an open-source, air-gapped Solana hardware signer. Keys are generated offline, held only in RAM, and never leave the device. Unsigned and signed transactions cross the gap as QR codes. There are no Faraday servers in the signing path.

Code and firmware: Faraday-signer/faraday (org Faraday-signer). Pure Rust signer core; browser extension and mobile companion complete the suite.

Security model

Life of a key (product + README)
Stage	Behavior
Birth	Entropy from camera frames mixed with HW RNG (and/or coin flips entered raw) — seed never weaker than either source
Storage	RAM only — no flash for keys; power off wipes seed
Network	No radios in the signing loop. Pi Zero 1.3: radio silicon absent. ESP32: drivers never linked; CI `nm` symbol audit
Review	Tx decoded offline from raw bytes; human-readable summary before approve (transfers, stake, Jupiter/Raydium-style swaps, Anchor calls, …)
Verify	Full stack OSS — build image and compare hashes to published release

Import warning (upstream): LOAD is for restoring a Faraday-born seed after power cycle / new device — not for migrating Phantom / Solflare / Backpack seeds. Online-born seeds stay compromised even if later signed air-gapped. Prefer create-on-Faraday then transfer assets.

Signing flow

text

[Phone / laptop]                         [Faraday air-gap]
  build unsigned tx
  show QR  ---------------------------->  camera scan
                                          decode + human review
                                          user approves
  scan signed QR  <--------------------  sign + display QR
  submit to Solana RPC
                                          power off → RAM wiped

Private key never crosses the gap.

Suite layout (monorepo)

Faraday-signer/faraday
Path	Role
`core/`	`faraday-core` — crypto, parser, signer, QR, GUI state
`raspberry-pi/`	Pi Zero firmware + desktop simulator
`esp32-common/` · `esp32-touch2/`	ESP32-S3 shared + Waveshare Touch LCD board
`opt/`	Buildroot recipe for Pi OS image
`extension/`	Chromium extension — Wallet Standard → QR relay
`mobile/`	React Native / Expo watch-only wallet for Solana Seeker (WIP)
`playground/`	Vite devnet dapp to exercise the extension

Hardware

Targets
Board	Notes	~Cost
Pi Zero 1.3 + Waveshare 1.3″ LCD + Pi Camera v1.3	Physical air gap (no WiFi/BT on v1.3 — not Zero W). Recommended.	~$35
Waveshare ESP32-S3-Touch-LCD-2	Self-contained touch + OV2640; radios on die but unused / audited	~$30

Quick start (no hardware)

bash

git clone https://github.com/Faraday-signer/faraday.git
cd faraday/raspberry-pi
cargo run --features simulator
# or from repo root: just sim

# CREATE → 12/24 WORDS → RANDOM
# Arrows = joystick · Enter/Z = confirm · Esc = back

End-to-end without Pi: run simulator + extension/ (npm run dev, load unpacked MV3) + playground/ dapp. See repo README for Windows/WSL camera notes (simulator_no_cam, usbipd, etc.).

When to use

Fit
Use Faraday	Use something else
High-value Solana keys; verify-everything culture	Convenience hot wallets for dust / daily micro spends
DIY / open BOM hardware	Vendor SE black-box if you accept closed firmware
QR air-gap + Wallet Standard dapps	USB-HID only workflows without camera/QR UX

Not related to Range’s “Faraday API” (stablecoin payments) — different product; this Faraday is the Solana air-gap signer.

Summary

Faraday is a verifiable Solana cold-signing stack: open firmware, memory-resident keys, QR-only I/O, optional Wallet Standard extension. Start with the desktop simulator, build or buy Pi Zero 1.3 for a physical air gap, and treat seed birth as a one-way offline event — not a migration from hot wallets.

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