Keystone

Keystone (formerly Cobo Vault) is an air-gapped hardware wallet built around a fully offline architecture. All transaction signing happens without USB data connections, Bluetooth, WiFi, or NFC. Instead, the device communicates with software wallets exclusively through animated QR codes and, optionally, a MicroSD card, so private keys never touch an internet-connected surface.

The current flagship is the Keystone 3 Pro, a hardware wallet with a 4-inch touchscreen and fingerprint biometric authentication. Its security foundation uses three secure element chips with PCI-grade tamper resistance and self-destruct protection against physical attacks. The device runs fully open-source firmware that users can verify independently, and the codebase has been audited by firms including Offside Labs, Blocksec, SlowMist, and KeyLabs.

Keystone integrates with 45+ software wallets, including MetaMask (official partner), OKX Web3 Wallet, Solflare, Keplr, and Rabby. The device supports multi-signature setups and PSBT (Partially Signed Bitcoin Transactions) for advanced transaction workflows. Users who want a reduced attack surface can install a Bitcoin-only firmware build rather than the full multi-coin option.

Supported assets include Bitcoin, Ethereum, XRP, Solana, BNB Chain, Cardano, Dogecoin, Litecoin, Polygon, and thousands of ERC-20 and other tokens across EVM-compatible and Cosmos-based networks, totalling 5,500+ cryptocurrencies. The device can hold up to three independent seed phrases, making it possible to manage separate asset categories on one unit without additional hardware.