Keystone Keystone 3 Pro
A plan byKeystone
Keystone is an air-gapped hardware wallet: it has no Bluetooth, Wi-Fi, NFC or USB data path, and signs every transaction via QR codes exchanged with the companion app. The Keystone 3 Pro model (≈€150) packs three Infineon secure elements (two certified CC EAL5+), a 4-inch touchscreen and a fingerprint reader. Firmware is open-source and the device works with third-party wallets such as MetaMask. It is made by Keystone (a Hong Kong-based company).
Keystone 3 Pro
- Price
- €150
What's included
- Air-gapped (QR signing)
- Three Infineon secure elements (2x EAL5+)
- 4-inch touchscreen
- Fingerprint reader
- microSD backup
Data & conditions
| Fund custody | Self-custody (funds in your control) |
|---|---|
| Type | Hardware (cold storage) |
| Source code | Partly open-source |
| Recovery | Seed phrase 12/24 parole (BIP-39); supporto multi-seed |
| Bitcoin-only | No |
| Supported chains | Bitcoin, Ethereum, Solana, Polygon, BNB Chain |
| Price | €150 |
| Secure element | Yes |
| Air-gapped | Yes |
| Connectivity | QR, microSD |
| Companion app | Keystone App |
| Built-in swap | No |
| Built-in staking | No |
| WalletConnect | No |
| Segment | B2C |
| MiCA / License status | Nessuna (hardware wallet self-custody) |
Strengths
- Genuinely air-gapped (QR signing, no USB/Bluetooth data); triple Infineon secure elements (2x EAL5+); open-source firmware; large touchscreen and fingerprint reader.
- Self-custody: funds stay in your wallet — the platform cannot touch them.
- No KYC: usable without identity verification.
- Self-hostable: you can run your own instance or node.
Weaknesses
- QR signing flow is more cumbersome than plain USB; requires the companion app and a phone camera; brand less known in Europe than Ledger/Trezor.
- No notable sovereignty drawback documented.
Verdict
Score 4.4/5, very strong profile. In its favour: genuinely air-gapped (QR signing, no USB/Bluetooth data); triple Infineon secure elements (2x EAL5+); open-source firmware; large touchscreen and fingerprint reader. The trade-off to weigh: qR signing flow is more cumbersome than plain USB; requires the companion app and a phone camera; brand less known in Europe than Ledger/Trezor.
On the Sovereignty lens the score is 4.3/5 (very strong): the strength is fund control (5.0/5), while trustless / auditability (2.5/5) is the weak link.
Promp's editorial rating based on real fees and net annual cost. Promp reviews third-party products independently.
"Sovereignty" rating: score computed on privacy/anonymity (30%), fund control (20%), censorship resistance (20%), trustless/auditability (20%) and costs (10%). Same data, different weights.
FAQ
How much does the Keystone 3 Pro cost?
The Keystone 3 Pro costs about €150 (€149.90 on the official shop and at European resellers).
Is Keystone really air-gapped?
Yes: it has no Bluetooth, Wi-Fi or NFC and the port is power-only. Every transaction is signed by exchanging QR codes with the app, with no direct data link.
Is Keystone open source?
Yes, the Keystone 3 Pro firmware is open-source and auditable. The device also pairs three Infineon secure elements, two of them certified CC EAL5+.
Sources
- hardware-wallets.net Secure element EAL5 · Infineon · QR · Companion Data verified on Jun 20, 2026
- shop.keyst.one Prezzo · Air gapped · Secure element · Open source Data verified on Jun 20, 2026