ETH Sign

The EthSignature class represents an Ethereum signature.

Used to parse the signed result returned by the device.

Inputs

Field	Value Type	Meaning
signature	Buffer	The signature data (65 bytes: r + s + v)
requestId	Buffer	The request ID (optional)
origin	string	The origin information (optional)

UR Demo

UR:ETH-SIGNATURE/OTADTPDAGDSWNNYAHGTOKPFPIAPANNROLNSAVYDTHHAOHDFPCATKCPPFYLENGAGLMKMUCAYKFPFSDREOMENTPKBGEONDCHFDNBKOSSTPDWETSGBZDNCMCHKPNYDMKIDPTDRYJSDRTKCTIOFPQZHFLNSKVACLMNIYTKLGISFRWLKTZTREAEAXIYGWJTIHGRIHKKPLGDEEDS

Decode Demo

import { URDecoder } from "@ngraveio/bc-ur";
import { EthSignature } from "@keystonehq/bc-ur-registry-eth";

const dec = new URDecoder();
// Feed each scanned frame string into the decoder
// feed each scanned frame into dec.receivePart(frame)

if (dec.isComplete()) {
  const ur = dec.resultUR(); // the decoded UR should be of type 'eth-signature'
  const signatureData = EthSignature.fromCBOR(ur.cbor);

  const requestId = signatureData.getRequestId();
  const signature = signatureData.getSignature();

  // Extract the r, s, and v components
  const r = signature.slice(0, 32);
  const s = signature.slice(32, 64);
  const v = signature.slice(64, 65);

  // Attach it to the transaction and broadcast
}

Signature Format

The signature is 65 bytes:

• r (32 bytes): First part of ECDSA signature
• s (32 bytes): Second part of ECDSA signature
• v (1 byte): Recovery ID