Hello Zcash Community,
I’m excited to share our grant application for REPUTRANS - a privacy-preserving reputation portability system for gig economy workers. We’ve been building this self-funded for several months, and we’re thrilled to bring it to the ZCG community for feedback and support.
GitHub Application: Grant Application - Reputrans · Issue #254 · ZcashCommunityGrants/zcashcommunitygrants · GitHub
Background
200+ million gig workers globally are locked out of fair financial services because their professional reputation is siloed inside platforms like Uber, Airbnb, and TaskRabbit. To get a loan or an insurance quote, they have to hand over full account access - sacrificing their privacy - or go without. There’s no way to prove “I have a 4.8-star rating and 1,200 completed trips” without also revealing exactly who you are and where you work.
REPUTRANS solves this using zero-knowledge proofs. Workers can prove their credentials meet a lender’s threshold without revealing their identity, the platform they work on, or their exact values. Verification happens entirely on-chain. No trusted intermediary, no data broker, no privacy compromise.
We’re led by Daniel Abraham (actuarial science background, 5 years in cyber insurance underwriting, ZK and Solidity engineer) and Kirill Slavin (MSc Applied Mathematics, previously founded a $100M+ fintech exit). We have a demonstrated track record: our previous project, Insuracle, completed both milestones of a Polkadot Fast Grant on time in June 2025.
What We’re Building
REPUTRANS is built across three cryptographic layers - each a first production implementation of a recently published academic construction:
1. U2SSO (Anonymous Identity) A Noir implementation of the U2SSO anonymous credential scheme (Zhang et al., 2025). Workers register a Pedersen commitment on-chain, creating an anonymity set via a Merkle tree. A nullifier prevents credential reuse.
2. ThetaCrypt (Threshold Credential Issuance) Real 3-of-5 threshold EdDSA signing on the Baby Jubjub curve using Shamir secret sharing and Lagrange interpolation. No single issuer can forge or revoke credentials unilaterally. First open-source implementation of ThetaCrypt (Aranha et al., 2025).
3. Map-to-Curve ZK Circuit An optimised Noir circuit (Pereira et al., 2025) achieving ~30 constraints versus ~7,000 in standard implementations - a 230x reduction - making proof generation practical on consumer hardware. First production implementation of this construction.
What We’re Proposing
Milestone 1 - Core Infrastructure & Testnet Deployment Full implementation of all three cryptographic layers in Noir, smart contract deployment and verification on Sepolia testnet, complete test suite, and developer documentation.
Milestone 2 - Dashboard, Open-Source Libraries & Community Credential issuance web dashboard (Next.js), open-source Noir library releases (Baby Jubjub, Pedersen commitments, threshold signature circuits), light security review, technical whitepaper, blog posts, and a community call with Zcash R&D Discord.
Budget Summary
| Category | Amount |
|---|---|
| Founders’ Compensation (Daniel + Kirill) | $30,000 |
| Senior Blockchain Engineer (Advisor) | $4,000 |
| Hardware (TEE server + laptop) | $2,500 |
| Software & Services | $1,464 |
| Security Review (light, 3rd party) | $3,000 |
| Grant Expenses (docs, travel, other) | $1,700 |
| Contingency | $2,336 |
| Total | $45,000 |
| Tranche | Amount | Trigger |
|---|---|---|
| Startup Funding | $10,000 | Grant approval |
| Milestone 1 | $17,500 | M1 acceptance |
| Milestone 2 | $17,500 | M2 acceptance |
Why Zcash?
The cryptographic libraries we’re building are directly applicable to the Zcash ecosystem. Our ThetaCrypt threshold EdDSA implementation shares the same mathematical foundations as FROST (maintained by the Zcash Foundation). Our Pedersen commitment and Baby Jubjub libraries are compatible with Zcash’s existing cryptography. Long-term, we see REPUTRANS as Zcash-native credential infrastructure first - credentials issued and verified on Zcash, with optional portability to Ethereum for interoperability benchmarking.
This is a real-world demonstration that ZK technology can solve financial inclusion problems for hundreds of millions of people, not just crypto-native use cases - and that Zcash is the right home for that infrastructure.
Links
- Pitch Deck: Reputrans_IC3_hackathon.pptx - Google Slides
We’d love to hear your feedback and answer any questions - especially from anyone working on FROST, ZK identity, or Zcash wallet infrastructure. Thank you for considering this proposal!
— Daniel Abraham & Kirill Slavin, Sibrox
daniel@sibrox.com | @danielabrahamx