Modules

ZeroJ is split into small modules so you only pull in what you use. All published artifacts share the Maven group org.zeroj, and every Java package starts with org.zeroj. (Releases up to 0.1.0-pre11 used com.bloxbean.cardano; see Migration notes.)

There are three kinds of published module:

• Core modules are version-aligned by the BOM org.zeroj:zeroj-bom-core. Import the BOM once and omit versions.
• Opt-in modules are published but deliberately left out of the BOM. Declare them with an explicit version. “Opt-in” means they’re not in the default dependency graph and have their own maturity; it doesn’t mean untested.
• Support, assurance and benchmark projects are never published.

Maturity labels come from the support matrix on Status & maturity. “Beta” means feature-complete and correctness-tested but not externally audited and not for value-bearing or mainnet use.

Using the BOM

build.gradle

dependencies {
    implementation platform('org.zeroj:zeroj-bom-core:0.1.0-pre12')

    implementation 'org.zeroj:zeroj-circuit-dsl'            // core: version from the BOM
    implementation 'org.zeroj:zeroj-crypto'
    implementation 'org.zeroj:zeroj-verifier-groth16'

    implementation 'org.zeroj:zeroj-bbs:0.1.0-pre12'    // opt-in: explicit version
}

pom.xml

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.zeroj</groupId>
      <artifactId>zeroj-bom-core</artifactId>
      <version>0.1.0-pre12</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

Core modules (in zeroj-bom-core)

Artifact	Purpose	Maturity	Start with
zeroj-api	Proof model and shared policy types. No dependencies.	Beta	ZkProofEnvelope, PublicInputs, VerificationKeyRef, VerificationMaterial, VerificationResult, CircuitId, CurveId, ProofSystemId, TrustedSetupPolicy, LegacyCurvePolicy
zeroj-codec	snarkjs JSON parsing, CBOR envelopes, canonical hashing	Beta	SnarkjsJsonCodec, CborEnvelopeCodec, CanonicalHash, EnvelopeValidator
zeroj-backend-spi	Verifier SPI, key registry, routing	Beta	ZkVerifier, BackendDescriptor, VerificationKeyRegistry, InMemoryVerificationKeyRegistry, VerifierRegistry, VerifierOrchestrator
zeroj-verifier-groth16	Groth16 BLS12-381 verification	Beta	Groth16BLS12381PureJavaVerifier (pure Java), Groth16BLS12381Verifier (blst-backed)
zeroj-bls12381	Pure-Java BLS12-381 fields, curves and pairing	Beta (verification-grade)	BLS12381Pairing, G1Point, G2Point, Bls12381Provider
zeroj-blst	Native BLS12-381 via blst: FFM MSM binding with a source-built, bundled libblst, plus pairing	Beta, opt-in native code	BlstBls12381Provider, BlstPairing, ffm.BlstFfm
zeroj-crypto	The pure-Java prover: Groth16 setup, proving, key stores, ceremony import, snarkjs export	Beta (Groth16); PlonK classes are experimental	Groth16Keys, Groth16Pipeline, Groth16ProverBLS381, Groth16SetupBLS381, PowersOfTauBLS381, ZkeyImporterBLS381, ZkeyPkStoreImporter, SnarkjsGroth16Json
zeroj-crypto-blst	Opt-in blst MSM backend for the Groth16 prover; bit-identical proofs	Beta, opt-in	BlstProverBackend
zeroj-circuit-dsl	Java circuit DSL; compiles to R1CS	Beta	CircuitBuilder, CircuitSpec, SignalBuilder, Signal
zeroj-circuit-lib	Gadget library: Poseidon, Merkle, comparators, binary, mux, Blake2b/SHA-512/HMAC, Ed25519/BIP32/CIP-1852…	Beta, per-gadget status	PoseidonParamsBLS12_381T3, see Gadgets
zeroj-circuit-annotation-api	@ZKCircuit symbolic annotations and Zk* types	Beta	@ZKCircuit, @Prove, @Public, @Secret, ZkField, ZkBool, ZkContext, ZkInputMap
zeroj-circuit-annotation-processor	Annotation processor that generates a <Name>Circuit companion class	Beta	Add as annotationProcessor
zeroj-onchain-julc	Plutus V3 validators and codecs, compiled with JuLC	Groth16: Beta, testnet only. PlonK validators: Experimental. BBS on-chain libraries: working for one fixed disclosure profile, not separately rated in the support matrix	groth16.validator.Groth16BLS12381Verifier, Groth16BLS12381TxOutRefBindingVerifier (reference example only), Groth16BLS12381Lib, ProverToCardano, SnarkjsToCardano, ScriptBudgetEstimator
zeroj-tools	Ceremony tooling and the zeroj-ceremony CLI (snarkjs-compatible phase-2 contributions)	Not separately rated; the ceremony design record is still Proposed	ZkeyContributor, SnarkjsHashToG2, CeremonyCli
zeroj-bom-core	The BOM for all of the above	—	platform('org.zeroj:zeroj-bom-core:…')

Two Groth16BLS12381Verifier classes

org.zeroj.verifier.groth16.bls12381.Groth16BLS12381Verifier (off-chain, blst-backed) and org.zeroj.onchain.julc.groth16.validator.Groth16BLS12381Verifier (on-chain validator) share a simple name. Import by package.

Opt-in modules (explicit version)

Artifact	Purpose	Maturity	Start with
zeroj-verifier-plonk	PlonK BLS12-381 verification (structured snarkjs/ZeroJ JSON)	Experimental	PlonkBLS12381Verifier
zeroj-bbs	CFRG BBS draft-10 signatures and selective disclosure	Verification: Beta. Issuance: Beta with caveat (use the blst provider for issuer keys)	BbsService, BbsPresentationCodec, BbsToCardano, BbsZkVerifier
zeroj-mpf-poseidon	Poseidon-rooted MPF adapter over Cardano Client Lib plus operation-specific circuits	Experimental	PoseidonMpfTrie, PoseidonMpfCircuitTemplates, PoseidonMpfBranchWitness
zeroj-jmt-poseidon	Poseidon-rooted JMT profile over Cardano Client Lib plus operation-specific circuits	Experimental	PoseidonJmtTree, PoseidonJmtCircuitTemplates, PoseidonJmtInclusionWitness

PlonK is experimental

Everything PlonK in ZeroJ (the prover classes in zeroj-crypto, zeroj-verifier-plonk, and the on-chain PlonK validators) is experimental and opt-in. Groth16 on BLS12-381 is the focus of the current release.

Legacy BN254 classes still exist in some modules for old off-chain experiments. They are disabled unless you set -Dzeroj.allowLegacyBn254=true, are not registered with ServiceLoader, and BN254 is not a Cardano curve.

What depends on what

You rarely need to list every module. Typical sets:

You want to…	Declare
Write and prove circuits	zeroj-circuit-dsl (+ zeroj-circuit-lib), zeroj-crypto; for annotations also zeroj-circuit-annotation-api and annotationProcessor 'org.zeroj:zeroj-circuit-annotation-processor'
Verify proofs in a service	zeroj-verifier-groth16, zeroj-codec
Verify on Cardano	zeroj-onchain-julc (+ JuLC’s julc-cardano-client-lib to load scripts)
Faster proving on big machines	add zeroj-crypto-blst and benchmark first
Credentials	zeroj-bbs (explicit version), optionally zeroj-blst

Never published

These live in the repository for testing, assurance and benchmarking. You can’t depend on them.

Project	What it is	How to build
zeroj-test-vectors	Shared fixtures: pre-generated proofs and VKs	Default build
zeroj-integration-tests	Cross-module regressions: Groth16 end-to-end, tampering, invalid witness, snarkjs interop, JuLC VM and Yaci DevKit	./gradlew :zeroj-integration-tests:test, :e2eTest
assurance/zeroj-bls12381-wasm	zkcrypto BLS12-381 compiled to WASM, an independent differential oracle (needs Rust)	-PincludeAssurance
assurance/zeroj-bbs-wasm	zkryptium BBS compiled to WASM, an independent differential oracle (needs Rust)	-PincludeAssurance
assurance/gnark-fixtures	Pinned gnark fixture generator for the committed PlonK vectors (needs Go)	make (not a Gradle project)
benchmarks/zeroj-mpf-poseidon-load	RocksDB load, proof and Cardano-artifact benchmark tool for MPF	-PincludeBenchmarks
benchmarks/zeroj-jmt-poseidon-load	Durable, versioned JMT load and benchmark tool	-PincludeBenchmarks

See Configuration for the build flags.

Next steps

• Installation
• API cheat sheet
• Status & maturity