Smartcard APDU probes

draft

The smartcard signer is the display-less custody line. Today it ships with a secp256k1-backed simulator plus a CLI that exchanges short APDUs with either the simulator or a real PC/SC reader when one is attached.

Install

The smartcard tools live in nSealr/smartcard.

git clone https://github.com/nSealr/smartcard
cd smartcard
make setup

Simulator: `GET_PUBLIC_KEY`

The simulator returns deterministic x-only public keys for fixture seeds.

$ nsealr-smartcard simulate get-public-key --seed-id 0
04a1b2…  (x-only, 32 bytes)

Simulator: `SIGN_EVENT_ID`

The simulator signs a 32-byte event id with the simulator’s secp256k1 keys. The signature is BIP-340 and verifiable against the shared fixtures.

$ nsealr-smartcard simulate sign-event-id \
    --seed-id 0 \
    --event-id 9f0c…2a
3045…  (BIP-340 signature)

PC/SC probe (when a reader is connected)

The same CLI can drive a real reader via pyscard. PC/SC commands fail clearly when pyscard or a reader is unavailable.

$ nsealr-smartcard probe get-public-key
ERROR: pyscard not installed, or no reader detected.

Status words

Smartcard responses carry deterministic status words defined by smartcard-apdu-v0. The companion / external reviewer compares them against the shared rejection vectors in nSealr/specs.