Block Bitkey

Bitkey is Block’s Bitcoin-only self-custody wallet. It combines a hexagonal hardware device with an OLED touchscreen and fingerprint sensor, the Bitkey phone app and a key held on Block’s servers into a 2-of-3 multisig wallet with no seed phrase. This page covers the current screen model, which Block introduced on 27 April 2026, not the first-generation device. Bitkey’s product page showed €230 when our dataset was checked on 14 October 2026; we have no US dollar listing on record. This page is built from Block’s documentation and disclosures; we have not used the device.

How does Bitkey work without a seed phrase?

The wallet has three keys, and any two of them approve a transaction or a change to security settings. Block’s product page describes them:

• Hardware key: “generated and stored completely offline in a secure enclave”, and enabled only by your fingerprint.
• App key: stored in the Bitkey app, with an encrypted backup copy in your personal cloud account.
• Server key: held by Block for recovery, in what Block calls an AWS Nitro Enclave.

Block says on its home page that it “cannot access or move your Bitcoin”, because one key alone cannot authorise a transaction. A single-signature wallet is backed up by its seed phrase, which BIP-39 lets you protect with a separate optional passphrase; Bitkey instead spreads signing across three keys in three places, one of them a company. That changes what you look after: a phone, a cloud account and a fingerprint-locked device, with Block’s server key as the third leg, rather than a sheet of words. Our self-custody guide covers the wider trade-off, and the Tangem Wallet shows a different seedless design built on backup cards.

What happens if you lose your phone or your Bitkey?

Block’s product page lists three cases:

• Lost phone: use the Bitkey device to decrypt the app-key backup in your cloud account.
• Lost Bitkey: get a new device and recover with the app on your phone.
• Lost both: Block points to its Recovery Contacts feature.

The product page also lists integrated inheritance, and its FAQ says you “can move your Bitcoin without the company” because you hold two of the three keys. Our dataset describes that route as relying on Bitkey’s recovery and exit tooling. We have not confirmed how it works on the screen model without the Bitkey app.

What is the Bitkey hardware like?

The product page lists an OLED touchscreen, a fingerprint sensor and a shell of Corian solid surface, at 66 x 60 x 13.6 mm and 79 g. The device talks to your phone over NFC and charges by USB-C, and Block quotes battery life of up to one year on a single charge. Phones need iOS 15.2 or later, or Android 7.0 or later with NFC. Block says every transaction and security setting is verified on the device. It does not publish the screen size in the sources we checked.

Is Bitkey open source?

Block publishes Bitkey’s app, firmware and server code in the proto-at-block/bitkey repository, whose licence file is the MIT License. The README calls it a published copy of Block’s internal repository, made available “for auditing purposes”, and says Block is not yet ready to support outside parties building every component. It documents a verifiable build for the Android app, with iOS to follow. We did not confirm which firmware in the repository matches the screen model, and binary reproducibility of the firmware was not tested.

In the sources we checked, Block names no secure element part or certification for this model. “Secure enclave” is Block’s wording, not a chip specification.

Has Bitkey been hacked?

None of the disclosures in our dataset is a reported theft. The four 2026 entries come from Block’s security updates page:

• 1 August 2026: a path using a modified app and a test relationship could shorten an inheritance claim’s review delay. Block reported a fix and no shortened customer inheritance claims.
• 11 August 2026: five software and infrastructure issues, covering delay checks on privileged actions, authorisation tokens in telemetry, randomness of an enrollment nonce, credential handling in release automation and authentication on an internal service. Block reported fixes and no customer impact.
• 2 October 2026: before onboarding, someone in close NFC range could, under specific timing conditions, pre-set an unlock PIN on a device. Block says this alone cannot reach funds but could allow wiping the device or starting a recovery that the owner can cancel. Fixed production firmware disables PIN unlock.
• 3 October 2026: a race in the signed-transaction cache of the Mobile Pay server, which tracks a daily spending allowance, could fail to count valid customer transactions against that allowance. Block reported a server fix and no customer impact.

Three of the four concern Block’s app or servers rather than the device. Because Block holds one of the three keys, its servers are part of the wallet’s security model.

What coins and apps work with Bitkey?

Bitcoin only. Setup needs both the Bitkey app and the device, according to Bitkey’s setup article. The 2-of-3 multisig is built in; we found no documentation for using Bitkey as a signer in other multisig coordinators. For how a phone-and-device setup compares with keeping keys entirely offline, see cold wallet vs hot wallet.

What we could not verify

• Screen size.
• The secure element part and any certification.
• Country of manufacture.
• Optional BIP-39 passphrase support; we found none documented.
• A US dollar price.
• How to move funds to another wallet without the Bitkey app on the screen model.

Our methodology explains how we source and date these records.