KeySigner Library

The KeySigner library is designed to simplify cryptographic operations involving the generation of digital signatures and the verification of those signatures. Built on top of Node.js's native crypto module, it abstracts away some of the complexities involved in handling keys and performing cryptographic signing and verification.

Installation

npm install @0xpass/key-signer

or

pnpm install @0xpass/key-signer

Usage

Initializing KeySigner

To create a new instance of KeySigner, you need to provide the private key. The private key can be supplied either as a path to a DER-encoded file in PKCS#8 format or as a base64-encoded string. This key can be generated using the openssl command-line tool, or the passport-scope cli passport-scope-cli package.

import { KeySigner } from "./path/to/keysigner";

// Using a file path
const signer = new KeySigner("/path/to/private_key.der");

// Using a base64-encoded string
const signerBase64 = new KeySigner("base64PrivateKeyString", true);

Creating a Signature

To sign data, use the createSignature method with the data you wish to sign as a string. This method returns the signature in a base64-encoded format.

const signature = signer.createSignature("data to be signed");
console.log(signature);

Creating a Signature Header

To create an HTTP header containing the signature, use the createSignatureHeader method. This can be useful for authenticated requests. This can be used for generating and formatting the correct headers for authentication requests to passport.

const { signatureHeaderName, signatureHeaderValue } =
  await signer.createSignatureHeader("data to be signed");
console.log(signatureHeaderName, signatureHeaderValue);

Verifying a Signature

To verify a signature, use the verifySignature static method, providing the original data, the signature to verify, and the public key. The public key can be supplied either as a path to a DER-encoded file in SPKI format or as a base64-encoded string.

const isVerified = KeySigner.verifySignature(
  "data to be signed",
  signature,
  "/path/to/public_key.der"
);
console.log(isVerified); // true or false