README

Assemble a Sigstore bundle — the .sigstore.json that cosign, gitsign and npm/PyPI provenance emit — from PHP. This is the counterpart to verification: hand it the pieces you already have (a signature or DSSE envelope, the Fulcio certificate, the Rekor entry) and it lays them out as the canonical v0.3 JSON that verifiers accept.

It does no signing and no network I/O — it is the format layer. The signature, the certificate and the transparency-log entry come from elsewhere (your signer, Fulcio, Rekor); this package places them in a well-formed bundle.

Requirements

• PHP 8.1+
• k2gl/dsse (for the DSSE envelope content)

Installation

composer require k2gl/sigstore-bundle

Usage

A DSSE-attestation bundle

use K2gl\SigstoreBundle\BundleBuilder;
use K2gl\SigstoreBundle\InclusionProof;
use K2gl\SigstoreBundle\TransparencyLogEntry;

$rekorEntry = new TransparencyLogEntry(
    logIndex: 148_384_212,
    logId: $logKeyIdBytes,
    kind: 'dsse',
    version: '0.0.2',
    canonicalizedBody: $canonicalBodyBytes,
    inclusionProof: new InclusionProof(
        logIndex: 148_384_212,
        rootHash: $rootHashBytes,
        treeSize: 148_384_213,
        hashes: $siblingHashBytes,       // list of raw hashes, bottom to top
        checkpoint: $signedCheckpoint,   // the signed note string
    ),
);

$json = BundleBuilder::forDsse($envelope)   // a K2gl\Dsse\Envelope you signed
    ->withCertificate($fulcioLeafDer)       // raw DER of the Fulcio leaf
    ->addTransparencyLogEntry($rekorEntry)
    ->toJson();

file_put_contents('artifact.sigstore.json', $json);

An artifact-signature bundle

use K2gl\SigstoreBundle\BundleBuilder;
use K2gl\SigstoreBundle\HashAlgorithm;
use K2gl\SigstoreBundle\MessageSignature;

$signature = new MessageSignature(
    algorithm: HashAlgorithm::SHA2_256,
    digest: $artifactSha256,   // raw 32-byte digest
    signature: $rawSignature,  // raw signature over the artifact
);

$json = BundleBuilder::forMessageSignature($signature)
    ->withCertificate($fulcioLeafDer)
    ->addTransparencyLogEntry($rekorEntry)
    ->addRfc3161Timestamp($rfc3161TokenDer) // optional trusted timestamp
    ->toJson();

Signing identity

Pick one, matching how the artifact was signed:

• ->withCertificate($der) — a single Fulcio leaf certificate (the keyless default).
• ->withCertificateChain([$leaf, $intermediate, $root]) — a full X.509 chain.
• ->withPublicKey($hint) — a key-based identity; the bundle only names the key by hint.

Compatibility

The output is byte-for-byte the same structure the reference tooling emits: the test suite rebuilds real cosign/GitHub v0.3 bundles (DSSE, message signature, and with an RFC 3161 timestamp) from their components and checks the result is identical. Bundles built here verify with k2gl/sigstore-verify and with cosign.

Pull requests are always welcome

Collaborate with pull requests