sigstore

What is sigstore?

The sigstore npm package provides tools for signing, verifying, and managing software supply chain security. It is designed to help developers ensure the integrity and authenticity of their software artifacts.

What are sigstore's main functionalities?

Signing Artifacts

This feature allows you to sign software artifacts, ensuring their integrity and authenticity. The code sample demonstrates how to sign an artifact using the sigstore package.

const sigstore = require('sigstore');

async function signArtifact() {
  const artifact = 'path/to/artifact';
  const signature = await sigstore.sign(artifact);
  console.log('Signature:', signature);
}
signArtifact();

Verifying Signatures

This feature allows you to verify the signatures of software artifacts. The code sample demonstrates how to verify an artifact's signature using the sigstore package.

const sigstore = require('sigstore');

async function verifySignature() {
  const artifact = 'path/to/artifact';
  const signature = 'signature-of-artifact';
  const isValid = await sigstore.verify(artifact, signature);
  console.log('Is valid:', isValid);
}
verifySignature();

Managing Keys

This feature allows you to generate and manage cryptographic keys. The code sample demonstrates how to generate a key pair using the sigstore package.

const sigstore = require('sigstore');

async function manageKeys() {
  const keyPair = await sigstore.generateKeyPair();
  console.log('Public Key:', keyPair.publicKey);
  console.log('Private Key:', keyPair.privateKey);
}
manageKeys();

Other packages similar to sigstore

openpgp

The openpgp package provides tools for OpenPGP encryption and signing. It offers similar functionalities to sigstore, such as signing and verifying artifacts, but it is based on the OpenPGP standard.

node-jose

The node-jose package is a JavaScript Object Signing and Encryption (JOSE) library. It provides tools for signing, verifying, and encrypting data, similar to sigstore, but it focuses on the JOSE standards.

jsonwebtoken

The jsonwebtoken package is used for signing and verifying JSON Web Tokens (JWT). While it is primarily focused on JWTs, it offers similar signing and verification functionalities as sigstore.

README

sigstore ·

A JavaScript library for generating and verifying Sigstore signatures. One of the intended uses is to sign and verify npm packages but it can be used to sign and verify any file.

Features

• Support for signing using an OpenID Connect identity
• Support for publishing signatures to a Rekor instance
• Support for verifying Sigstore bundles

Prerequisites

• Node.js version >= 14.17.0

Installation

npm install sigstore

Usage

const { sigstore } = require('sigstore')

import { sigstore } from 'sigstore'

sign(payload[, options])

Generates a Sigstore signature for the supplied payload. Returns a Sigstore bundle containing the signature and the verification material necessary to verify the signature.

• payload <Buffer>: The bytes of the artifact to be signed.
• options <Object>
  • fulcioURL <string>: The base URL of the Fulcio instance to use for retrieving the signing certificate. Defaults to 'https://fulcio.sigstore.dev'.
  • rekorURL <string>: The base URL of the Rekor instance to use when adding the signature to the transparency log. Defaults to 'https://rekor.sigstore.dev'.
  • tsaServerURL <string>: The base URL of the Timestamp Authority instance to use when requesting a signed timestamp. If omitted, no timestamp will be requested.
  • tlogUpload <boolean>: Flag indicating whether or not the signature should be recorded on the Rekor transparency log. Defaults to true.
  • identityToken <string>: The OIDC token identifying the signer. If no explicit token is supplied, an attempt will be made to retrieve one from the environment.

attest(payload, payloadType[, options])

Generates a Sigstore signature for the supplied in-toto statement. Returns a Sigstore bundle containing the DSSE-wrapped statement and signature as well as the verification material necessary to verify the signature.

• payload <Buffer>: The bytes of the statement to be signed.
• payloadType <string>: MIME or content type describing the statement to be signed.
• options <Object>
  • fulcioURL <string>: The base URL of the Fulcio instance to use for retrieving the signing certificate. Defaults to 'https://fulcio.sigstore.dev'.
  • rekorURL <string>: The base URL of the Rekor instance to use when adding the signature to the transparency log. Defaults to 'https://rekor.sigstore.dev'.
  • tsaServerURL <string>: The base URL of the Timestamp Authority instance to use when requesting a signed timestamp. If omitted, no timestamp will be requested.
  • tlogUpload <boolean>: Flag indicating whether or not the signed statement should be recorded on the Rekor transparency log. Defaults to true.
  • identityToken <string>: The OIDC token identifying the signer. If no explicit token is supplied, an attempt will be made to retrieve one from the environment.

verify(bundle[, payload][, options])

Verifies the signature in the supplied bundle.

• bundle <Bundle>: The Sigstore bundle containing the signature to be verified and the verification material necessary to verify the signature.
• payload <Buffer>: The bytes of the artifact over which the signature was created. Only necessary when the sign function was used to generate the signature since the Bundle does not contain any information about the artifact which was signed. Not required when the attest function was used to generate the Bundle.
• options <Object>
  • ctLogThreshold <number>: The number of certificate transparency logs on which the signing certificate must appear. Defaults to 1.
  • tlogThreshold <number>: The number of transparency logs on which the signature must appear. Defaults to 1.
  • certificateIssuer <string>: Value that must appear in the signing certificate's issuer extension (OID 1.3.6.1.4.1.57264.1.1). Not verified if no value is supplied.
  • certificateIdentityEmail <string>: Email address which must appear in the signing certificate's Subject Alternative Name (SAN) extension. Must be specified in conjunction with the certificateIssuer option. Takes precedence over the certificateIdentityURI option. Not verified if no value is supplied.
  • certificateIdentityURI <string>: URI which must appear in the signing certificate's Subject Alternative Name (SAN) extension. Must be specified in conjunction with the certificateIssuer option. Ignored if the certificateIdentityEmail option is set. Not verified if no value is supplied.
  • certificateOIDs <Object>: A collection of OID/value pairs which must be present in the certificate's extension list. Not verified if no value is supplied.
  • keySelector <Function>: Callback invoked to retrieve the public key (as either string or Buffer) necessary to verify the bundle signature. Not used when the signature was generated from a Fulcio-issued signing certificate.
    • hint <String>: The hint from the bundle used to identify the the signing key.

tuf

The tuf object contains utility function for working with the Sigstore TUF repository.

client([options])

Returns a TUF client which can be used to retrieve targets from the Sigstore TUF repository.

• options <Object>
  • tufMirrorURL <string>: Base URL for the Sigstore TUF repository. Defaults to 'https://tuf-repo-cdn.sigstore.dev'
  • tufRootPath <string>: Path to the initial trusted root for the TUF repository. Defaults to the embedded root.
  • tufCachePath <string>: Absolute path to the directory to be used for caching downloaded TUF metadata and targets. Defaults to a directory named "sigstore-js" within the platform-specific application data directory.

The returned object exposes a getTarget(path) function which returns the contents of the target at the specified path in the Sigstore TUF repository.

getTarget(path[, options]) (deprecated)

Returns the contents of the target at the specified path in the Sigstore TUF repository. This method has been deprecated and will be removed in the next major version. You should use the TUF client function to retrieve a stateful TUF client and then call getTarget against that object. This will avoid re-initializing the internal TUF state between requests.

• path <string>: The path-relative-url string that uniquely identifies the target within the Sigstore TUF repository.
• options <Object>
  • tufMirrorURL <string>: Base URL for the Sigstore TUF repository. Defaults to 'https://tuf-repo-cdn.sigstore.dev'
  • tufRootPath <string>: Path to the initial trusted root for the TUF repository. Defaults to the embedded root.
  • tufCachePath <string>: Absolute path to the directory to be used for caching downloaded TUF metadata and targets. Defaults to a directory named "sigstore-js" within the platform-specific application data directory.

utils

The utils object contains a few internal utility functions. These are exposed to support the needs of specific sigstore-js consumers but should NOT be considered part of the stable public interface.

CLI

The sigstore-js library comes packaged with a basic command line interface for testing and demo purposes. However, the CLI should NOT be considered part of the stable interface of the library. If you require a production-ready Sigstore CLI, we recommend you use cosign.

$ npx sigstore help
sigstore <command> <artifact>

  Usage:

  sigstore sign         sign an artifact
  sigstore attest       sign an artifact using dsse (Dead Simple Signing Envelope)
  sigstore verify       verify an artifact
  sigstore version      print version information
  sigstore help         print help information

Credential Sources

GitHub Actions

If sigstore-js detects that it is being executed on GitHub Actions, it will use ACTIONS_ID_TOKEN_REQUEST_URL and ACTIONS_ID_TOKEN_REQUEST_TOKEN environment variables to request an OIDC token with the correct scope.

Note: the id_token: write permission must be granted to the GitHub Action Job.

See https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect for more details.

Environment Variables

If the SIGSTORE_ID_TOKEN environment variable is set, it will use this to authenticate to Fulcio. It is the callers responsibility to make sure that this token has the correct scopes.

Interactive Flow

If sigstore-js cannot detect ambient credentials, then it will prompt the user to go through the interactive flow.