Class MTCContentSigner

java.lang.Object
org.bouncycastle.cert.plants.MTCContentSigner
All Implemented Interfaces:
ContentSigner
public class MTCContentSigner extends Object implements ContentSigner
Issuer-side ContentSigner that emits an MTC signatureValue (an encoded MTCProof) for an EE Merkle Tree certificate per Section 6.1 of draft-ietf-plants-merkle-tree-certs.

The signer is plugged into the standard X509v3CertificateBuilder.build(ContentSigner) flow. As the TBSCertificate DER bytes stream out of the builder into getOutputStream(), this class captures them; when getSignature() is invoked it:

  1. Derives the MerkleTreeCertEntry leaf hash and climbs one Merkle level using the single-sibling inclusionProof via MerkleTreeCertificateValidator.computeSubtreeHash(byte[], byte[], MerkleTreeHash).
  2. Delegates to MTCCosigner.cosignSubtree(MTCLog, byte[]) to produce the cosigner's MTCSignature.
  3. Wraps the inclusion proof and the cosigner signature in an MTCProof and returns its TLS wire encoding.

This is the simple-case binding used by the worked examples: a standalone certificate (Section 6.2 of the draft) over the minimal subtree [0, 2) — the EE's log entry at index 0, one sibling leaf at index 1, and a single-node inclusion proof — carrying one cosigner signature. Issuers with multi-level inclusion proofs or multiple cosigners should compose the MTCCosigner, MTCProof and MerkleTreeHash primitives directly; landmark-relative certificates (Section 6.3, no signatures) are built via LandmarkCertificateManager.buildLandmarkCertificate(long, long, TBSCertificateLogEntry, SubjectPublicKeyInfo, MerkleTreePrimitives.SubtreeInfo, List, MerkleTreeHash).

  • Constructor Details

    • MTCContentSigner

      public MTCContentSigner(MTCLog log, byte[] inclusionProof, MTCCosigner cosigner)
      The cosigner's identity is taken from MTCCosigner.getCosignerId() — the CA-as-cosigner case is just a MTCCosigner constructed with log.getCa().getCaId() as its cosigner ID (Section 5.3 of the draft). Witnesses, regulators, federated peers or any other entity with a distinct trust anchor ID work via the same constructor by constructing the cosigner with their own ID.
      Parameters:
      log - issuance log + subtree window [log.getStart(), log.getEnd()) — also supplies the CA (via MTCLog.getCa()) and therefore the hash function and log ID
      inclusionProof - the single sibling leaf hash that, combined with the EE's leaf hash, yields the subtree hash — same bytes that land in the resulting MTCProof
      cosigner - cosigner driver bound to its trust anchor ID, signature algorithm and key

  • Method Details

    • getAlgorithmIdentifier

      public org.bouncycastle.asn1.x509.AlgorithmIdentifier getAlgorithmIdentifier()
      Description copied from interface: ContentSigner
      Return the algorithm identifier describing the signature algorithm and parameters this signer generates.
      Specified by:
      getAlgorithmIdentifier in interface ContentSigner
      Returns:
      algorithm oid and parameters.

    • getOutputStream

      public OutputStream getOutputStream()
      Description copied from interface: ContentSigner
      Returns a stream that will accept data for the purpose of calculating a signature. Use org.bouncycastle.util.io.TeeOutputStream if you want to accumulate the data on the fly as well.
      Specified by:
      getOutputStream in interface ContentSigner
      Returns:
      an OutputStream

    • getSignature

      public byte[] getSignature()
      Description copied from interface: ContentSigner
      Returns a signature based on the current data written to the stream, since the start or the last call to getSignature().
      Specified by:
      getSignature in interface ContentSigner
      Returns:
      bytes representing the signature.