Bitkey

Overview

Bitkey, from Block (the company behind Cash App and Square), reimagines Bitcoin self-custody without a seed phrase. Instead of one device holding one key you must back up, Bitkey is a Bitcoin-only 2-of-3 multisig system: one key lives on a small NFC hardware device, one on your phone app, and one is held by Block's servers as a recovery key. To spend, you need any two of the three. This removes the scariest part of self-custody for newcomers — the fragile written seed phrase — while keeping you in control.

The design is thoughtful: for everyday spending your phone plus the hardware device (tapped via NFC) sign transactions, so Block isn't involved in normal use. Block's key only comes into play for recovery, and recovery involves time delays and identity checks to resist theft. The hardware is open-source, Bitcoin-only, and uses a secure element and a fingerprint sensor.

The honest trade-off is the trust and privacy question. You are relying on Block to hold one of the three keys and to run the recovery process fairly and remain in business. Because it's 2-of-3, Block alone can never move your funds (it holds only one key), which is the crucial safeguard; but you're still depending on their infrastructure for recovery and accepting that a company knows about your wallet. For newcomers who want self-custody without seed-phrase anxiety and trust Block for the recovery role, it's a genuinely innovative option; sovereignty maximalists who want zero third parties should choose a conventional wallet.