Attestix Java Verifier

Offline verifier for Attestix-issued credentials, in pure Java. Verify Ed25519 W3C Verifiable Credentials and UCAN delegation chains that were issued by the Attestix Python core — with no Python runtime needed.

This is a language port of the Attestix verifier. It reproduces the Attestix canonical form byte-for-byte and is validated against the shared cross-language conformance vectors (spec/verify/v1/vectors.json in the parent repo, vendored here under testdata/ and src/test/resources/).

This port is verifier-only: it verifies credentials and delegation chains; it does not issue them. Issuance stays in the Attestix Python core (pip install attestix) or Attestix Cloud.

• Parent project: https://github.com/VibeTensor/attestix
• Bundle wire-format spec: https://attestix.io/spec/bundle/v1
• Ed25519 via BouncyCastle (trusted, deterministic)

Canonical form note. Attestix uses a JCS-style canonical form, not strict RFC 8785. The load-bearing divergence: Attestix applies Unicode NFC normalization to every string value and object key (RFC 8785 does not), and whole-number floats collapse to integers (1.0 → 1). See CANONICAL.md for the full rules.

Install

Maven (once published to Maven Central):

<dependency>
  <groupId>io.vibetensor</groupId>
  <artifactId>attestix</artifactId>
  <version>0.4.0</version>
</dependency>

Gradle (Kotlin DSL):

implementation("io.vibetensor:attestix:0.4.0")

Requires Java 11+ at runtime. (CI builds and tests on Temurin 17.)

Verify a credential (10 lines)

import io.vibetensor.attestix.*;
import java.time.Instant;

// The issuer's did:key (published out of band, e.g. in the agent card).
byte[] issuerKey = DidKey.decode("did:key:z6Mko5TBPGKHkCxSgmf3aC6p6SGj2auwCfRmBydXJFEwL4ev");

String vcJson = /* the credential JSON, e.g. read from a file */ "...";
VerificationResult r = Attestix.verifyCredential(vcJson, issuerKey, Instant.now());

System.out.println("signature valid: " + r.signatureValid());
System.out.println("not expired:     " + r.notExpired());
System.out.println("not revoked:     " + r.notRevoked());
System.out.println("overall verify:  " + r.verify());   // AND of all checks

Verify a delegation chain

byte[] serverKey = DidKey.decode("did:key:z6Mko5TBPGKHkCxSgmf3aC6p6SGj2auwCfRmBydXJFEwL4ev");
DelegationResult d = Attestix.verifyDelegationChain(parentJwt, childJwt, serverKey, Instant.now());
// d.verify() == every JWT signature valid AND child att ⊆ parent att AND not expired

UCAN delegations are EdDSA JWTs (compact form), not JCS-signed. Only alg=EdDSA is accepted (alg:none is rejected). Capability attenuation is enforced: a child's capabilities must be a subset of its parent's.

Decode a did:key

byte[] rawEd25519 = Attestix.decodeDidKey("did:key:z6Mko5TBPGKHkCxSgmf3aC6p6SGj2auwCfRmBydXJFEwL4ev");
// rawEd25519 is the 32-byte public key (multibase base58btc + 0xed01 multicodec prefix)

Canonicalize JSON (the Attestix way)

byte[] canonical = Attestix.canonicalize("{\"b\":2,\"a\":1}");
// -> bytes of {"a":1,"b":2}  (keys sorted by code point, no whitespace, raw UTF-8, NFC)

Public API

Method	Purpose
Attestix.verifyCredential(vcJson, issuerKey, now)	Verify a W3C VC → VerificationResult
Attestix.verifyDelegationChain(parent, child, serverKey, now)	Verify a UCAN chain → DelegationResult
Attestix.canonicalize(json)	JCS-style canonical UTF-8 bytes
Attestix.decodeDidKey(did)	did:key:z… → raw 32-byte Ed25519 key

VerificationResult exposes signatureValid(), notExpired(), notRevoked(), structureValid(), and verify().

Build & test

./gradlew test     # runs the conformance vectors
./gradlew build    # jar + sources + javadoc

CI (.github/workflows/test.yml) builds and runs the vectors on Temurin 17 with SHA-pinned actions.

Conformance

Every vector in testdata/vectors.json is asserted by src/test/java/io/vibetensor/attestix/ConformanceVectorsTest.java:

Vector	What it checks
canon-001	JCS-style canonical bytes (NFC, sorted keys, whole-float→int, big int)
didkey-001	did:key decode (0xed01 multicodec, 32-byte key) + round-trip
vc-valid-001	Valid VC → verify true
vc-tampered-001	Tampered claim → signature invalid → verify false
vc-expired-001	Expired VC → not_expired false → verify false
ucan-chain-valid-001	Delegation chain, child att ⊆ parent att → verify true
ucan-chain-escalation-002	Privilege escalation (admin not in parent) → verify false

Releasing to Maven Central

This build is publish-ready (POM metadata, sources + javadoc jars, GPG signing wired) but is not auto-published. To cut a release:

1. Configure Sonatype OSSRH / Central Portal credentials (OSSRH_USERNAME, OSSRH_PASSWORD) and a GPG key (SIGNING_KEY, SIGNING_PASSWORD) as environment variables or Gradle properties.
2. ./gradlew publish to stage to OSSRH.
3. Close & release the staging repository (or use the Central Portal UI).

No tokens are committed; publishing is a manual, credentialed step.

License

Apache-2.0. See NOTICE.