Fid
An airgapped signer for the BLAKE2b chain and nostr. Import a key, sign a PSBT, sign a nostr event. Nothing is stored. Close the tab and the key is gone.
Checking this build against the vectors…
Chain
Import a key
64 hex characters, an nsec, or a WIF. Fid never generates keys. Use a device you trust, offline.
This key
npub
x-only pubkey
address on
Sign a PSBT
Base64 or hex. Every input needs a witness utxo. Inputs paying to this key's untweaked taproot output get signed. On the BLAKE2b chains the signature opts in to the unified sighash (0x21), on the SHA256d chains it is BIP341 default. A blocktrail update is just a PSBT here.
Signed
Sign a nostr event
Paste an unsigned event (NIP-01 JSON). The pubkey is filled from the key, or must match it.