The Frontier

Block’s new Bitkey hardware wallet includes a screen for a more intuitive self-custody experience, and the company envisions seamless ecosystem connectivity where a paycheck converts in Cash App and auto-withdraws to self-custody.

Block will roll out a public Bitcoin roadmap across Square, Cash App, Bitkey, and Proto to build in public and allow community influence on development priorities.

Max Guise states BitKey's design started by solving the hardest problems in self-custody, focusing first on recovery and safety to lower entry barriers for new users who found traditional setup overly technical.

BitKey aims to eliminate seed phrases, using a collaborative custody system with a hardware wallet, mobile app, and Block's servers. This addresses the vulnerability of portable seed phrases in potential wrench attacks.

The new BitKey hardware adds on-device verification with a screen, allowing users to directly confirm transaction details, receive addresses, and critical account security changes like email and SMS updates.

BitKey's onboarding process takes minutes from unboxing to first transaction, a core design goal to make the door into self-custody easy and attract users gifting devices to others.

BitKey implemented Chain Code Delegation, proposed as BIP89, to allow users to benefit from a third key held by Block's servers without the privacy trade-off of the server knowing wallet balances and history.

To counter wrench attacks, BitKey is designing a vault system using time locks enforced by hardware and servers, requiring biometric checks and a configurable delay before funds can move, with an optional ejection destination.