Keystone 3 Pro

Keystone 3 Pro uses a triple secure element architecture — ATECC608B, DS28S60, and MAX32520 (CC EAL6+) — providing defence-in-depth key protection. All transaction signing is done via QR code with no USB data connection, eliminating USB-based attack surfaces. A critical firmware vulnerability was patched in v2.0.4 in March 2025; all users should be running that version or later. No confirmed exploitation of the vulnerability was reported.

In March 2025, Keystone disclosed a critical firmware vulnerability affecting Keystone 3 Pro devices running firmware prior to v2.0.4. The flaw could allow a malicious transaction to be signed without the expected on-screen verification under specific conditions. Keystone released v2.0.4 as a mandatory critical update. No confirmed exploitation in the wild was reported. Devices still running firmware below v2.0.4 should update immediately.

Keystone 3 Pro uses three separate certified secure element chips: an ATECC608B, a DS28S60, and a MAX32520 certified to CC EAL6+. This triple-chip architecture means no single chip holds enough information to extract private key material. It is the most redundant secure element configuration of any mainstream consumer hardware wallet available as of 2025.

Keystone 3 Pro supports Bitcoin, Ethereum (including ERC-20 tokens), Solana, Cosmos, Polkadot, and several hundred additional assets across multiple blockchains. It is one of the most broadly compatible hardware wallets available. Multi-coin breadth does mean a larger firmware codebase than Bitcoin-only devices, which is worth considering when evaluating the overall attack surface.

The Keystone 3 Pro firmware is partially open source. The application firmware and secure element firmware are both published on GitHub. However, some proprietary components are used in the hardware design. Users who require a fully open-source hardware stack should review the published repositories and audit documentation to determine whether the level of transparency meets their requirements.