zeroj-codec

zeroj-codec

Proof serialization for ZeroJ — snarkjs JSON parsing, CBOR encoding, and canonical hashing.

This module bridges external proof tooling (snarkjs, gnark) and ZeroJ's internal model. It parses proof artifacts into ZkProofEnvelope objects and provides deterministic serialization for network transmission and content addressing.

Features

Class	Description
SnarkjsJsonCodec	Parse snarkjs proof.json, verification_key.json, public.json into ZeroJ types
SnarkjsProof	Record holding Groth16 proof coordinates (piA, piB, piC) + protocol + curve
SnarkjsVerificationKey	Record holding VK points (alpha, beta, gamma, delta, IC)
CborEnvelopeCodec	Deterministic CBOR serialization of ZkProofEnvelope (integer-keyed map)
CanonicalHash	SHA-256 hash of canonical VK encoding for content addressing
EnvelopeValidator	Validates envelope fields before verification
GnarkPlonkCodec	Typed envelope codec for gnark binary PlonK proof artifacts; verification still uses gnark native verification until a structured adapter exists
Halo2Codec	Codec for Halo2 proof artifacts

Groth16 snarkjs JSON and CBOR envelope parsing use bounded input reads, duplicate-key detection, canonical decimal checks, and typed CodecException failures for malformed input.

Usage

// Parse snarkjs artifacts
var proof = SnarkjsJsonCodec.parseProof(proofJson);
var vk = SnarkjsJsonCodec.parseVerificationKey(vkJson);
var publicInputs = SnarkjsJsonCodec.parsePublicInputs(publicJson);

// Build envelope directly from JSON files
var envelope = SnarkjsJsonCodec.toEnvelopeFromJson(proofJson, vkJson, publicJson,
        new CircuitId("multiplier"));

// CBOR encode/decode for network transmission
byte[] cbor = CborEnvelopeCodec.encode(envelope);
ZkProofEnvelope decoded = CborEnvelopeCodec.decode(cbor);

// Compute canonical hash for content addressing
byte[] hash = CanonicalHash.hash(envelope);

Gradle

dependencies {
    implementation 'com.bloxbean.cardano:zeroj-codec'
}