SeedLock
// start

Get started

SeedLock lives on a computer that is never online. Download it, copy it over, and make your first backup.

// security features

Security features

Strict air-gap enforcement and network kill switch

SeedLock doesn’t just ask you to stay offline; it enforces it.

  • Refuses to run. If your computer or phone is connected to a network, SeedLock will not open.
  • Network kill switch. SeedLock checks the network every single second. If a Wi-Fi signal drops in or a cable is plugged in while your seed is open, a built-in kill switch instantly wipes the screen, clears the terminal history, and shuts the app down to protect your keys.
// download and installation

Download and install SeedLock

Download, check and start SeedLock, step by step. Click to open.

You use two computers. On your online computer you get the program. On the offline computer, which is never connected to a network, you run it. The offline computer needs only one file.

1. Download

On the online computer, open the Releases page. Under the newest release, download SHA256SUMS.txt, its signature (SHA256SUMS.txt.asc), the release key (release-key.asc, in the docs folder) and the program for your offline computer:

Windows (64-bit)seedlock-0.3.0-windows-x86_64.exe
Mac (Apple chip and Intel)seedlock-0.3.0-macos
Linux (64-bit Intel or AMD)seedlock-0.3.0-linux-x86_64
Android (preview)seedlock-0.3.0-android.apkFor a spare phone kept in airplane mode.

2. Check the download (SHA-256 and GPG)

Open a terminal (PowerShell on Windows) in your Downloads folder and compute the program’s SHA-256 fingerprint:

Windows(Get-FileHash seedlock-0.3.0-windows-x86_64.exe).Hash
Macshasum -a 256 seedlock-0.3.0-macos
Linuxsha256sum seedlock-0.3.0-linux-x86_64

Compare the long number with the one next to the program’s name in SHA256SUMS.txt. They must match exactly.

For the highest security, also check the GPG signature. It proves that the checksum list itself comes from the maintainer:

gpg --import release-key.asc gpg --verify SHA256SUMS.txt.asc SHA256SUMS.txt

It must say Good signature and show the release key fingerprint:

E435 21D9 44AE 9BAA 9FB2 D11D 08B6 5FB6 5CB1 D806

Optional: camera and QR window (ffmpeg)

Do you need it? No. SeedLock works without it: you can move transaction files on a USB stick. But if you want to scan Sparrow’s QR codes with a webcam, and show SeedLock’s QR codes in a pop-up window, you need the free program ffmpeg.

Important: install or copy it to the offline computer before you disconnect that computer from the internet for good.

Linux (Debian, Ubuntu)sudo apt install ffmpeg
Linux (Arch)sudo pacman -S ffmpeg
Macbrew install ffmpegThen allow Terminal to use the camera in System Settings > Privacy & Security.
Windowsffmpeg-release-essentials.zipNo installation needed. Download it from gyan.dev and copy ffmpeg.exe and ffplay.exe from its bin folder into the same folder as seedlock.exe.

3. Move to the offline computer and start

Rename the program to seedlock. Copy it, with SHA256SUMS.txt, to a USB stick, and then into a folder of its own on the offline computer. Tip: check the SHA-256 fingerprint one last time on the offline computer.

Start it from its own folder:

Windowsdouble-click seedlock.exe
Linux and Mac./seedlockOpen a terminal in the folder first.

macOS and Windows show a security warning the first time, because SeedLock is independent software. The full guide explains how to open it safely.

SeedLock works only offline: if the computer is connected to a network, it shows SEEDLOCK WORKS ONLY OFFLINE and waits until you disconnect. You can also build the program yourself from the source code.

Status: version 0.3.0, not independently audited. Try it on testnet, or with a small amount, first.

DownloadFull installation guide
// tutorial

Your first backup

// interactive menu

First steps

  1. Create your seed: menu 1. Write the words on paper, type three back to prove it, and keep the paper safe. Give the backup a name and press Enter to generate a strong password for your password manager.
  2. Check that it opens: menu 4.
  3. Keep copies: save the backup file on a USB stick or in the cloud, and keep the password somewhere else.
  4. Set up Sparrow: menu 5. SeedLock shows what Sparrow Wallet needs for a watch-only wallet, with no secret.
  5. Sign a payment: menu 6. Sparrow prepares it, SeedLock shows every address and amount, and signs only if you say yes.
User guide
// android

Android phone

SeedLock for Android is a preview. It turns a spare phone into a portable, air-gapped signing device. It makes the same encrypted backups and signs the same payments as the computer version.

  1. Download seedlock-0.3.0-android.apk from the Releases page. It is in the same signed list as the computer programs.
  2. Install it on the phone. The Android guide explains how.
  3. Strictly offline, with a network kill switch. Keep the phone in airplane mode, with Wi-Fi, mobile data and Bluetooth off. If a connection accidentally turns on while the app is open, a built-in kill switch instantly closes every screen.
Get the Android apkAndroid guide