Learn TAPSIGNER

TAPSIGNER is the Bitcoin signing key your phone does not keep. A compatible wallet constructs and displays the transaction; the NFC card keeps the BIP-32 private key separate and signs after PIN authentication. The card has no screen, so the wallet remains the place where you review amounts, destinations, fees, and change.

Start with the task you need to complete

Understand the signer

• What is TAPSIGNER? explains the division of responsibility between the wallet and card.
• How screenless signing works explains what key isolation protects and what a malicious wallet can still misrepresent.
• TAPSIGNER security model covers entropy, factory certificates, CVC authentication, backup, and recovery assumptions.

Set up and recover

• Set up TAPSIGNER with Nunchuk follows the official onboarding sequence without relying on stale button labels.
• Backup and recovery explains the encrypted XPRV file, printed 128-bit decryption key, derivation path, and no-restore boundary.
• Compatible wallets lists the integrations currently presented by the official site and links to each publisher.

Use it in a policy

• Use TAPSIGNER as a multisig cosigner covers quorum design, descriptors, derivation paths, common-mode risk, and recovery tests.
• Integrate TAPSIGNER is the protocol and security checklist for wallet developers.
• SATSCARD vs TAPSIGNER answers whether the card should change owners or stay with one signer.

The model in one table

Component	Responsibility	Important boundary
Companion wallet	Build and display transactions, manage addresses and wallet policy, broadcast	A compromised wallet can show false details or request an unintended signature
TAPSIGNER	Hold the BIP-32 key, derive hardened paths, sign authenticated digests	No screen; it cannot independently show amount, destination, fee, or change
User	Verify card and app, preserve recovery material, review before tapping	A tap and PIN authorize what the card was asked to sign
Backup	Encrypted master XPRV file plus separate printed decryption key	Recovery exposes the XPRV to the recovery environment and cannot restore another card

TAPSIGNER is not a payment card, SATSCARD-style bearer instrument, BIP-39 seed-phrase wallet, multi-asset wallet, or display-equipped transaction-verification device.

Need operational help?

Choose an official integration on Get Started, then follow the wallet publisher's current instructions. Use the FAQ for detailed product questions and the public protocol for implementation details.