Key Highlights
- QuantumLink replaces manual device-to-app transfers with a real-time Bluetooth connection between Passport Prime and Foundation’s Envoy app.
- Passport Prime uses a dedicated Bluetooth chip isolated from KeyOS, with end-to-end encryption protecting every message.
- Users can disable Bluetooth and use QR codes, NFC or USB instead.
How QuantumLink Connects Passport Prime to Envoy
Foundation’s QuantumLink protocol replaces the manual transfer process with a real-time Bluetooth connection between Passport Prime and Envoy, the company’s companion app. According to Herbert’s explanation, the connection supports device onboarding, transaction signing, firmware updates and synchronization.
Foundation’s security model relies on physical separation. Passport Prime uses a dedicated, isolated Bluetooth chip that operates independently of KeyOS, the wallet’s primary security processor. Although the Bluetooth chip carries communications, it is not permitted to read the data passing through it. Every message is end-to-end encrypted before it reaches the chip.
The Cryptography Behind QuantumLink
QuantumLink uses two cryptographic tools in sequence. CRYSTALS-Kyber manages the key exchange, allowing the wallet and Envoy app to establish a shared secret. ChaCha20-Poly1305 then encrypts the messages exchanged during each session.
Kyber provides the post-quantum element of the system. Its role is to protect the initial handshake against attackers equipped with quantum computers, in addition to defending against conventional threats. ChaCha20-Poly1305 protects the individual messages after the secure connection has been established.
The pairing process adds a separate security layer. Before Bluetooth communication begins, Passport Prime and the app exchange public keys out of band through a QR code. Because the initial key exchange does not occur over Bluetooth, the Bluetooth chip does not receive plaintext data. If the chip were compromised, an attacker would obtain encrypted traffic without the information needed to decrypt it.
Bluetooth Is Optional on Passport Prime
Foundation has also retained non-wireless options for users who prefer a more restrictive security setup. Passport Prime allows Bluetooth to be disabled completely, with QR codes, NFC or USB available as alternatives. Users are therefore not required to use the Bluetooth connection to operate the wallet.
From QR Air-Gapping to Quantum Resistance
Foundation’s case for QuantumLink builds on its earlier work in Bitcoin self-custody. The company’s previous device, Passport Core, introduced QR-based air-gapping before being discontinued.
QuantumLink was publicly introduced on January 23, 2025. Foundation developed the protocol with Blockchain Commons during the design phase. Details about Passport Prime, which launched with QuantumLink integrated, emerged on March 26, 2026.
Herbert, who has advocated for Bitcoin since 2013, has explained the protocol across multiple platforms, including X and CoinDesk.
Why This Matters
QuantumLink addresses a central trade-off in hardware wallet design: Bluetooth can make onboarding, transaction approval and firmware management more convenient, but wireless connectivity also creates concerns about attack surfaces and data exposure.
Foundation’s approach attempts to separate convenience from the wallet’s primary security functions by assigning Bluetooth communications to an isolated chip while encrypting messages end to end. Community discussions have focused on Bluetooth-related vulnerabilities, leaving Foundation to demonstrate that the physical separation performs in practice as intended by the architecture.
Frequently Asked Questions
What is QuantumLink?
QuantumLink is Foundation’s protocol for connecting Passport Prime to the Envoy companion app through real-time Bluetooth communication. It supports onboarding, transaction signing, firmware updates and synchronization.
How does Passport Prime protect data sent over Bluetooth?
Passport Prime uses a dedicated Bluetooth chip that is isolated from KeyOS. Public keys are exchanged through a QR code before Bluetooth communication begins, and messages are protected with CRYSTALS-Kyber and ChaCha20-Poly1305 encryption.
Can Bluetooth be disabled on Passport Prime?
Yes. Users can disable Bluetooth entirely and use QR codes, NFC or USB instead.
