State-of-the-art seed phrase backup.

Penlock is an open-source, cryptographically secure, printable paper-computer. It guides users through secret-splitting their BIP39 seed phrase without an electronic device.

Hello Everyone!

You are browsing the pre-release of Penlock, specially made available for the Bali Bitcoin Week! At that time, the illustrated examples are being worked on. However, I'll be here in the workshops to teach you how to use it, and receive your precious feedback. Have a good week in Bali!

Getting things done

Generate a Seed Phrase

Generate a 12-word seed phrase using real-world, provable randomness.

-> Open the Guide

Split a Seed Phrase

Split a seed phrase into 3 (encrypted) shares. Any two of these shares can be used to recover the original seed phrase, but a single compromised share reveals nothing about it.

-> Open the Guide

Recover a Seed Phrase

Recover a seed phrase from 2 Penlock shares belonging to the same set.

-> Open the Guide