v0.9.0

Changelog

• Using custom ganache from docker container
• Fixes for documentation typos
• CI fixes and robustness improvements
• Clean-up in serialization logic
• Move curve and snark specific code into dependent library (libsnark)
• Update libsnark and libff
• Upgrade grpc to 1.44

0.8 - Drachma

Changelog

Features and improvements

• Refactor the MiMC round constant generation scripts and support constants for
  up to 93 rounds

  • PRs: #376

• Add zeth-tool for advanced operations (manipulating objects, serializing,
  verifying proofs etc)

  • PRs: #377, #378, #385

• Improved genericity of the client to allow for different JSIN/JSOUT values

  • PRs: #378

• Add prover profiling operations

  • PRs: #382

• Clean up client dependencies and bump major for web3.py

  • PRs: #384, #389, #403

• Rely exclusively on estimateGas in the client

  • Issues: #295, #281
  • PRs: #390

Optimizations

• Migrate serialization functions to libff and pull libff optimizations
  • PRs: #382

Tooling

• Add scripts for generating large circuits and build on EC2 instances

  • PRs: #385

• Upgrade to actions/checkout to the v2 in all CI scripts

  • PRs: #397

• Extend Doxygen configuration and add CI for docs generation

  • PRs: #393, #402

Code quality

• Rename bits<numBits>::fill_variable_array to bits<numBits>::fill_pb_variable_array for consistency

  • PRs: #396

• Rename inconsistent commands (CLIs, executable scripts etc) to stick to kebab-case

  • PRs: #392

Fixes

• Fix interface of sha256 gadget to remove the need for the ZERO pb_variable

  • Issues: #387
  • PRs: #391

• Fix access specifiers in gadget inheritance tree

  • PRs: #395

0.7 - Daric

Changelog

Features

• Zecale support for Zeth transaction aggregation

  • Related PRs: #343, #344, #345, #349

• Data structures serialization/deserialization improvements

  • Related PRs: #358

• Support native cpp snark verifier

  • Related PRs: #358

• New flags for prover_server command to export data

  • Related PRs: #368

Security fixes

• Bump cryptography python package from 3.2 to 3.3.2

  • Related PRs: #353

• Upgrade solidity code to 0.8 solidity version (to support safe arithmetic, non-experimental ABIEncoderv2 etc.)

  • Related issues: #96, #149
  • Related PRs: #352

Optimizations

• Swith MiMC round function degree and corresponding round numbers
  • Related issues: #364
  • Related PRs: #369

Tooling

• Ran contract tests as part of the CI

  • Related PRs: #341

• Support caching on the CI and add integration tests

  • Related issues: #324, #150
  • Related PRs: #326

• Migrate docker build from Docker Hub to Github Container Regisry

  • Related PRs: #350

• Better code re-use for the Continuous Integration

  • Related PRs: #354

• Update custom ganache-cli to bring changes in libff used in bls12-377 and bw6-761 precompiled contracts

  • Related PRs: #347, #362

Code quality

• Solidity code cleanup to align with newly established coding standards
  • Related issues: #321, #335
  • Related PRs: #361, #366

Fixes

• Fixed R1CS serialization

  • Related PRs: #346

• Fix test data for Groth16 to ease cross-library tests with NeoDIZK

  • Related PRs: #365

0.6 - Obol

Changelog

Features

• Extend prover_server configuration to the client

  • PR: #293
  • Issue: #292

• Full support for BLS12-377

  • PRs: #298, #297

• Client and smart contracts refator to improve configuration management and abstract curve operations

  • PR: #302

• More generic MiMC operations (templatized gadgets and configuration):

  • PRs: #309, #323

Security fixes

None

Optimizations

• Improved object encodings:

  • PR: #283

• More compact encoding of smart-contract arguments

  • PR: #288

• Negate B attribute of Groth16 arguments for simpler and more efficient SNARK verification on-chain

  • PR: #287

Code quality

• Solidity coding standards and switch from solium to solhint linter

  • PRs: #318, #333

• Improved type management in the client

  • PR: #289

Testing

• Enable tests on all supported curves
  • PR: #327

Tooling

• Support for ganache-cli to enable BW6-761 and BLS12-377 precompiled contracts
  • PR: #280

Build and CI

• Enable docker images build and push to DockerHub via Github Actions

  • PR: #313
  • Issue: #278, #258

• Split (and enhancement) of the CI workflows

  • PRs: #284, #330
  • Issue: #320

• Enable code scanning on the CI:

  • PRs: #319, #322, #336
  • Issue: #304

Documentation

• Extend contribution guide

  • PR: #317

• Adoption of NatSpec documentation comments for solidity code

  • PR: #321
  • Issue: #192

0.5-Sigloi

Changelog

Features

• Generalize MPC code to support curves other than bn256

  • PR: #223
  • Issue: #176

• Add support for generic serialization of field and group elements

  • PRs: #232, #220

• Refactor and improve serialization functions in the server code (C++) and in the client code (Python)

  • PR: #237

• Change semantics of --keypair flag on prover_server to easily import/export the SRS

  • PRs: #248, #261
  • Issues: #260, #242

• Extend client to work with Ethereum-like clients (e.g. Autonity, Geth etc.)

  • PR: #253, #241, #239

• Add --show-parameters flag to zeth mix command

  • PR: #263

• Add support for TLS in the client

  • PR: #267

Fixes

• Fix the serialization of the VK

  • #221

• Fix JSON output of PGHR13 arguments

  • PR: #218

• Fix linking issues with boost when building pot-process

  • PR: #231

• Fix tests for the MerkleTreeMiMC7.sol contract

  • PR: #229
  • Issue: #228

• Fix the mpc code and documentation (support streaming when sending challenges, fix path to binaries, switched time to UTC)

  • PRs: #266, #264

• Add extra logging information and extend MPC contribution window in CI script to troubleshoot macOS job failing on the CI:

  • PRs: #269

Security fixes

None

Optimizations

None

Tooling

• Switched to latest Ubuntu LTS (20.04) in CI

  • PR: #227

• Add IS_ZETH_PARENT build option to avoid build rule name collision when Zeth is used as a dependency

  • PR: #235

• Add script to process and recover the full SRS from several chunks (useful for the distribution)

  • PR: #256

• Extend docker configuration to package the various components of the code base (prover_server, client, mpc) into separate images

  • PR: #257, #272
  • Issue: #234, #12

Code quality

• Adopt a consistent naming for types and type-params

  • PR: #233

• Support full parameterization in the library and clean the configuration of the snark and curve types

  • PR: #225

• Refine the clang-tidy configuration and add cpp_check in the CI checks

  • PRs: #213, #212

• Refactor and repackage the client

  • PR: #254

• Remove useless notestore folder an rename env variables in setup_env.sh

  • PR: #259

• Use a single namespace for tests in libzeth

  • PR: #276

Documentation

• Add reference to the Zeth protocol specifications

  • PR: #226

• Add missing flags to client

  • PR: #250

• Include missing documentation to the Doxygen documentation output

  • PR: #277

0.4-Croeseid

Changelog

Features

• Zeth wallet CLI

  • Related issues: #144, #168, #162, #165
  • Related PRs: #130, #154, #145, #184, #189, #204, #166

• Improved field element serialization to support bigints with arbitrary number of limbs

  • Related PRs: #175, #182

Security fixes

• Fix replay attack allowing to steal "vout"

  • Related issues: #160
  • Related PRs: #161

• Use IK-CCA encryption scheme to encrypt note data

  • Related issues: #2
  • Related PRs: #193, #199

Optimizations

• Smart contracts optimizations

  • Related issues: #94
  • Related PRs: #138

• Reduced number of primary inputs - saving scalar multiplications for the verifier

  • Related issues: #52, #170
  • Related PRs: #80, #171, #148

• Use the full blake2s hash function as commitment scheme instead of custom multiple calls to the compression function - saving a call to the compression function for each commitment

  • Related issues: #158
  • Related PRs: #190

Tooling

• Switch from Travis to Github Actions

  • Related issues: #164
  • Related PRs: #167

• Use formatting in CI

  • Related PRs: #172

• Switch from Ubuntu to Alpine as base image for Zeth Docker image

  • Related issues: #194
  • Related PRs: #195, #197

• Improve and fix the build

  • Related PRs: #202

• Add LLVM sanitizers options to the build and support tools to enforce code conventions/best practices, generate documentation and code coverage reports, and carry out static analysis.

  • Related PRs: #208

Code quality

• Change project structure and refactor of the c++ code

  • Related issues: #98, #178
  • Related PRs: #151, #177, #200, #206, #207, #210, #211, #214

• Improved test structure

  • Related PRs: #209

• Parameterized circuit

  • Related issues: #153
  • Related PRs: #185

• Refactor of proto files and API-related files

  • Related PRs: #201

0.3-Lydia

Changelog

Features

• Refactor of the APIs to build a layer of abstraction for proof systems used in the backend and ease the support for multiple proof systems:

  • Related issues: #3
  • Related PRs: #19

• Support for the Groth16 SNARK:

  • Related issues: #3
  • Related PRs: #22

• Multi-party computation protocol for the SRS generation of Groth16:

  • Related issues: #20, #90, #95, #105
  • Related PRs: #40, #41, #48, #67, #68, #73, #76, #77, #78, #88, #119

• Support for higher denomination private payments:

  • Related issues: #24
  • Related PRs: #101

• Support for R1CS export in json format and minimal R1CS-json parser to analyze the Arithmetic Circuit:

  • Related PRs: #124

Security fixes

• Fix the transaction malleability attack:

  • Related issues: #7, #120
  • Related PRs: #43, #59, #61, #132

• Fix a double spend attack based on modular arithmetic on primary inputs:

  • Related issues: #38
  • Related PRs: #74, #85

Circuit optimizations

• Switch to MiMC-based compression function in the Merkle tree of commitments:

  • Related issues: #4
  • Related PRs: #34, #42

• Switch to Blake2s compression function to instantiate COMMs and PRFs:

  • Related issues: #49
  • Related PRs: #63, #81, #87

Other enhancements

• Better tooling to maintain and raise code standards:
  • Related issues: #57, #60
  • Related PRs: #62, #65

These come along with various PRs to enhance code quality (#25, #29, #64, #110, #114, #121)

• Refactor of the build:

  • Related issues: #10, #37, #46
  • Related PRs: #28, #32, #33, #39, #47

• Refactor of the Python client to split functionalities into separate modules and use type annotations

  • Related issues: #56, #113
  • Related PRs: #107, #111, #112, #127

0.2-Sproken

This release of the PoC contains:

• A complete re-write of the circuit from ZCash sprout
• A new version of the mixer contract that now implements a single function able to support deposits, transfers and withdrawals of arbitrary denominations.
• A prover server that implements a RPC interface and can listen to incoming requests from clients (requests can be of two natures: fetching the verification key to instantiate an on-chain verifier smart contract for instance, or requesting the generation of a proof on a given input)
• Two clients (one in javascript, the other in python) that show how Zeth can work, by requesting proofs generation to the prover server and executing a few confidential asset transfers on a local Ethereum test network.

Note: The name of the release is a play on word between "Sprout" (ZCash before Sapling) and "Broken" as this PoC is not secure (see the checks removed in the circuit from the original Zcash version)