Void Market

Terms and Conditions

• I agree to the Grant Agreement terms if funded
• I agree to Provide KYC information if funded above $50,000 USD
• I agree to disclose conflicts of interest
• I understand that this grant program is only eligible for completed work, as it is a retroactive grant program. Applications for planned or partially completed work will not be considered. All completed work will be verified and accepted by its intended users or their representatives, who will confirm that the outputs meet the required quality, functionality, and usability before the work is listed as an option for Coinholder voting.
• I agree that for any new open-source software, I will create a CONTRIBUTING.md file that reflects the high standards of Zcash development, using the librustzcash style guides as a primary reference.
• I understand when contributing to existing Zcash code, I am required to adhere to the project specific contribution guidelines, paying close attention to any merge, branch, pull request, and commit guidelines as exemplified in the librustzcash repository.
• I understand all grants are valued in USD but will be disbursed in Shielded ZEC. I acknowledge and accept that disbursement amounts may fluctuate based on the ZEC/USD exchange rate at the time of payment.

Application Owners (@octocat, @octocat1)

@binqbit

Organization or Individual Name

Dmytro Sysoliatin

Additional Team Members

N/A

How did you learn about the Lockbox: Coinholder Retroactive Grants Program?

Through AI-assisted research and the official announcement on the Zcash Community Forum.

Requested Grant Amount (USD)

15000

Category

Non-Wallet Applications

Project Summary

Void Market is an open-source sealed-bid auction application that combines confidential bid comparison with Zcash shielded payments. It demonstrates a workflow for selecting an eligible winning bid and settling the resulting transaction without publicly exposing bid amounts or the seller’s reserve price.

Project Description

Void Market is an open-source sealed-bid auction application combining confidential bid comparison with Zcash shielded payments. Buyers submit confidential bids, while sellers keep their reserve prices private. The application determines the eligible winning offer without publicly disclosing these amounts and uses shielded Zcash payments to settle the resulting transaction.

The current version implements this workflow through an automated arbiter operated by the project. Under honest execution, the arbiter processes the auction without learning individual bid amounts. This version retains a trust assumption: the operator must not collude with a participating bidder to disclose unauthorized competitive information.

The project’s goal is to make confidential auctions and shielded settlement usable as a practical, integrated workflow, demonstrating how Zcash can support private commerce beyond standalone payments.

The planned version 2 aims to enable independently operated arbiters. We intend to develop additional cryptographic proofs that make specified deviations from the agreed auction rules verifiably attributable to the arbiter, including misconduct that could expose confidential information. Combined with an enforceable collateral and compensation mechanism, this would make proven abuse financially punishable and give independent operators an incentive to follow the agreed rules. The objective is to reduce reliance on a trusted operator through verifiable accountability.

Technical Approach (how you did it)

Void Market v1 separates confidential auction evaluation from payment settlement. The application coordinates buyer bids, the seller’s private reserve price, an automated arbiter, and Zcash shielded payment verification.

Auction evaluation uses homomorphic computations and comparisons, together with one-time masks for intermediate values exchanged during the protocol. Homomorphic operations support computation over protected inputs, while masking limits disclosure during intermediate verification steps. Participant responses are checked for consistency with the protocol. The intended output identifies the winning eligible offer and whether it satisfies the seller’s reserve, rather than publishing the underlying bid amounts or reserve price.

Version 1 uses an automated arbiter operated by our platform. During normal protocol execution, the arbiter does not learn individual bid amounts. The identified confidentiality risk involves collusion between the platform operator and a participating bidder, which could expose confidential competitive information. The current threat model therefore requires trust that the platform will not engage in such collusion.

The settlement workflow uses Zcash shielded payments. After auction selection, the winning buyer receives a payment request. Payment is verified against the agreed auction outcome, and the seller confirms the transaction. Relevant payment information can be selectively disclosed for dispute resolution without publishing the entire payment history.

The application also coordinates an Ethereum-side asset-release workflow. The asset remains under arbiter control until the required payment conditions are met, after which it can be released to the buyer or returned on cancellation. This is coordinated cross-chain execution, not an atomic swap.

The work followed a research-first process over approximately one month. Several weeks were devoted to developing the core protocol: brainstorming the mechanism, working through its mathematical and cryptographic reasoning, analyzing its guarantees and threat model, comparing alternative designs, and checking its behavior through exploratory prototypes and test examples. The protocol’s guarantees were considered together with their trust assumptions, including the collusion-related limitation of version 1.

During the final week, the protocol rules and conditions were consolidated into documentation and technical specifications, followed by implementation of the integrated application workflow. This brought together confidential auction evaluation, automated arbiter coordination, shielded payment verification, and coordinated asset release in version 1. The source code was published for review and reuse.

Version 2 is planned to support independently operated arbiters through additional cryptographic evidence of specified misconduct and a collateral-backed compensation mechanism. These mechanisms are future development goals and are not claimed as implemented version 1 capabilities.

Time Period of Work Completion

October 2026

Total Budget (USD)

6525

Budget Breakdown

• Compensation:

  • $(USD): 6,000
  • Justification: Compensation for my own development work on the completed Void Market v1, including protocol implementation, application integration, and testing.

• Technology/Software:

  • $(USD): 500
  • Justification: $300 in additional Codex credits purchased specifically for this project, plus an estimated $200 allocation of my ChatGPT/Codex subscription cost based on the project's share of my development usage. The subscription allocation is an estimate, not an exact metered project charge.

• Infrastructure/Hosting:

  • $(USD): 25
  • Justification: Estimated combined allocation for server hosting and domain registration associated with the project.

• Services/Contractors:

  • $(USD): 0
  • Justification: No external contractor costs included in this budget.

• Other:

  • $(USD): 0
  • Justification: No other costs included in this budget.

• Total $(USD): 6,525

Previous Funding

No

Previous Funding Details

No response

Other Funding Sources

Yes

Other Funding Sources Details

Void Market has been submitted to ZECATHON, a Zcash hackathon. The results are pending, and no prize funding has been received to date. If awarded, I intend to use the prize to support further development of the project. This is a potential funding source, not a confirmed award.

Success Metrics

Completed contribution

Void Market v1 is an open-source application combining confidential auction evaluation with Zcash shielded payments, payment verification, and selective disclosure for disputes. Its source code is publicly available for inspection and reuse.

We do not yet report verified external adoption or transaction-volume metrics. The evidence below supports the relevance of the problem; it is not a claim of measured product adoption.

Evidence of community need

• Commerce privacy beyond payments — December 1, 2025. In Shielding the Context of Commerce: Closing the Metadata Gap, GGuy discusses how private payments can still leave purchase context, identity, and receipts exposed.

• Marketplace privacy — August 26, 2026. The ZEC Market team describes a goal of enabling commerce without a middleman holding funds or seeing what users buy. Its description also includes public listings and prices. This is a developer-stated objective, not an independent customer testimonial.

• Operator visibility into auction bids — October 2026. ShadowBid was described on the Zcash forum. Its documented privacy model states that the server receives bid amounts and secrets during reveal, and that the operator can access valid revealed bids. This illustrates the distinction between hiding bids from the public and hiding them from the auction operator.

Void Market’s approach and current trust boundary

During normal execution, Void Market v1 does not reveal individual bid amounts to its automated arbiter. It retains a trust assumption: collusion between the platform operator and a participating bidder could expose some confidential information.

The planned version 2 aims to support independent arbiter operators through cryptographic evidence of specified misconduct and collateral-backed compensation. These are future development goals, not completed outcomes.

Evaluation outlook

The sources above establish relevant community discussion and documented implementation trade-offs. They do not establish adoption or independent validation of Void Market.

Future evaluation should measure independent reproduction of the complete workflow, real auction usage, and the reliability of settlement and dispute handling.

Proof of completion

• Repository/Commit:
  • Repository — Public source code for Void Market.
• Publication:
  • N/A
• Deployment/Release:
  • Application — Void Market application website.
• Other Evidence:
  • N/A

Conflict of Interest Disclosure

No response

Community Forum Posting

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