Overview
Keystone is an open-source air-gapped hardware wallet that signs cryptocurrency transactions through QR codes rather than USB, Bluetooth, WiFi, or NFC, eliminating wired and wireless attack surfaces entirely1. The flagship Keystone 3 Pro device supports Cardano alongside Bitcoin, Ethereum, XRP, Solana, and dozens of other chains, and pairs with leading software wallets including MetaMask, OKX Wallet, Eternl, and Rabby2.
Key Features
- Air-gapped QR signing. The device has no USB data port, Bluetooth, WiFi, or NFC; all communication with companion software happens by scanning QR codes through a built-in camera and screen1.
- Triple secure element chips. Three independent secure element chips isolate private key material, paired with a PCI-grade self-destruct mechanism that responds to physical tampering3.
- Open-source firmware. Firmware and tooling are published under the KeystoneHQ organization on GitHub, with the Keystone 3 Pro firmware written primarily in Rust for memory safety4.
- Multi-seed support. A single device can hold up to three independent seed phrases, allowing users to separate funds across personas or set up plausible-deniability vaults without buying multiple units1.
- Touchscreen and fingerprint. A four-inch touchscreen displays full transaction details for verification, and a fingerprint sensor handles unlock and signing approvals.
What to Expect
Setup follows the standard hardware wallet pattern: generate a recovery phrase on the device, write it down (or punch it into a steel backup plate), and verify. Day-to-day use means keeping the Keystone offline and pairing it with a software wallet on a phone or computer. To send a transaction, the software wallet displays a QR code that the Keystone scans through its camera; the device shows decoded transaction details on its screen, the user approves with a fingerprint, and a signed-transaction QR is scanned back into the software wallet for broadcast.
For Cardano users, the practical pairing path is through Cardano-native software wallets such as Eternl, which expose the QR signing flow alongside their normal staking and DApp connector features. The hardware adds a verification step but does not change how users interact with the broader Cardano ecosystem. Keystone descends from the earlier Cobo Vault product line and has built relationships with security firms including SlowMist, Offside Labs, and BlockSec for ongoing review2.
