n_signer CYD Web Serial Demo

Connection

Connect to the CYD (CH340 serial) via Web Serial, then exercise every algorithm and verb in the n_signer API. Chrome/Edge/Brave/Opera only.

Disconnected

No approval required. Safe to call before the mnemonic is loaded.

Algorithm Index

nostr_index format

Algorithm Index scheme (secp256k1 only) message (hex — 32 bytes / 64 hex for schnorr)

peer pubkey hex (1184 bytes / 2368 hex) — leave empty to use self pubkey index (for decapsulate) ciphertext hex (for decapsulate)

peer pubkey hex (32 bytes / 64 hex) index

data (UTF-8 string) index (required)

content nostr_index

Slow on ESP32 — uses single-threaded PoW. Keep difficulty low.

content nostr_index difficulty (leading zero bits) timeout (sec)

peer pubkey hex (32-byte x-only) plaintext ciphertext (for decrypt) nostr_index

peer pubkey hex (32-byte x-only) plaintext ciphertext (for decrypt) nostr_index

OTP pad is derived from the mnemonic on the CYD. Offset advances monotonically.

plaintext (base64) ciphertext (for decrypt, base64) encoding

A browser control panel for the CYD (ESP32-2432S028) signer firmware. Speaks the n_signer JSON-RPC protocol over Web Serial at 115200 baud.

1. Plug the CYD into a USB port (CH340 enumerates as /dev/ttyUSB*).

2. Click Connect Web Serial and pick the CYD port.

3. get_info fires automatically and reports firmware version + supported verbs.

4. Enter a mnemonic on the CYD touchscreen to enable the signing verbs.

Every request is signed with a demo secp256k1 key (priv = 0x0102…2020). The CYD verifies the kind-27235 auth event and replays-protects by event id.

Frames are 4-byte big-endian length + UTF-8 JSON payload. Same wire format as the host Unix-socket and TCP transports.

demo v1