ecdsa-sig-formatter

What is ecdsa-sig-formatter?

The ecdsa-sig-formatter npm package is used to convert ECDSA signatures from ASN.1/DER encoded format to JOSE/JWT compact serialization format and vice versa. This is particularly useful when working with JWTs and other security tokens in Node.js applications.

What are ecdsa-sig-formatter's main functionalities?

DER to JOSE conversion

Converts a DER-encoded ECDSA signature to JOSE format. The second parameter ('ES256') specifies the algorithm used, which determines the expected size of the signature.

const ecdsaSigFormatter = require('ecdsa-sig-formatter');
const derSignature = '...'; // DER-encoded signature
const joseSignature = ecdsaSigFormatter.derToJose(derSignature, 'ES256');

JOSE to DER conversion

Converts a JOSE-encoded ECDSA signature to ASN.1/DER format. Similar to the previous function, the algorithm ('ES256') needs to be specified.

const ecdsaSigFormatter = require('ecdsa-sig-formatter');
const joseSignature = '...'; // JOSE-encoded signature
const derSignature = ecdsaSigFormatter.joseToDer(joseSignature, 'ES256');

Other packages similar to ecdsa-sig-formatter

jose

A comprehensive package for JSON Object Signing and Encryption (JOSE). It supports various JOSE operations including ECDSA signature formatting. It is more feature-rich than ecdsa-sig-formatter, providing a complete set of JOSE tools for encryption, decryption, signing, and verification.

node-jose

Another package that provides a set of utilities for parsing, generating, and processing JOSE objects. It is similar to 'jose' and offers a wider range of functionalities compared to ecdsa-sig-formatter, which is more focused on signature formatting.

pem-jwk

This package converts between PEM encoded RSA and ECC keys and JWKs. While it does not directly handle ECDSA signatures, it is related in the sense that it deals with key format conversions, which is a complementary operation to what ecdsa-sig-formatter does.

README

ecdsa-sig-formatter

Translate between JOSE and ASN.1/DER encodings for ECDSA signatures

Install

npm install ecdsa-sig-formatter --save

Usage

var format = require('ecdsa-sig-formatter');

var derSignature = '..'; // asn.1/DER encoded ecdsa signature

var joseSignature = format.derToJose(derSignature);

API

---

.derToJose(Buffer|String signature, String alg) -> String

Convert the ASN.1/DER encoded signature to a JOSE-style concatenated signature. Returns a base64 url encoded String.

• If signature is a String, it should be base64 encoded
• alg must be one of ES256, ES384 or ES512

---

.joseToDer(Buffer|String signature, String alg) -> Buffer

Convert the JOSE-style concatenated signature to an ASN.1/DER encoded signature. Returns a Buffer

• If signature is a String, it should be base64 url encoded
• alg must be one of ES256, ES384 or ES512

Contributing

1. Fork the repository. Committing directly against this repository is highly discouraged.

2. Make your modifications in a branch, updating and writing new unit tests as necessary in the spec directory.

3. Ensure that all tests pass with npm test

4. rebase your changes against master. Do not merge.

5. Submit a pull request to this repository. Wait for tests to run and someone to chime in.

Code Style

This repository is configured with EditorConfig and ESLint rules.