Grant Application: ZecShield — Universal Privacy Bridge between Solana and Zcash
Applicant: Andrii Dumitro
Requested Amount: $48,000 USD
Duration: 8 months (May 2026 – December 2026)
Category: Infrastructure
Summary
ZecShield is a trust-minimized bridge between Solana and Zcash that allows any SPL token to be shielded in Zcash’s Orchard pool using FROST threshold signatures (3-of-5) with economic bonds. The bridge operates entirely through a web interface — no desktop client required.
Project Description
ZecShield is a production-ready specification and implementation of a bridge that connects Solana and Zcash for the first time, allowing any SPL token to be shielded in Zcash’s Orchard pool.
The Problem Being Solved
Zcash has the best-in-class privacy technology — the shielded Orchard pool with Halo 2 proof system. Already, 59% of Zcash transactions go through the private pool.
However, Zcash is completely isolated from the broader crypto market. Currently, there are no production-grade bridges connecting Zcash to any major blockchain. Liquidity in Zcash’s shielded pool remains limited.
At the same time, Solana’s TVL exceeds $4 billion, the network has over 1 million daily active wallets, and hundreds of liquid SPL tokens.
Because of this gap:
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Zcash users cannot bring external assets into the shielded pool;
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Solana users cannot access best-in-class privacy.
Solution: ZecShield
ZecShield is a production-ready bridge between Solana and Zcash with minimal trust. It allows any SPL token to be shielded in Zcash’s Orchard pool using FROST threshold signatures (3-of-5) with economic bonds.
The bridge works exclusively through a web interface — no Zcash desktop client required. Interaction happens via familiar Solana wallets: Phantom, Backpack.
How This Helps Zcash
1. Increased Liquidity and Activity
The bridge will attract large volumes of tokens from Solana’s developed DeFi ecosystem. This will increase the usage, demand, and value of Zcash. Zcash will cease to be an isolated cryptocurrency.
2. Support for Any Solana Token
Unlike existing bridges that work with a limited set of assets, ZecShield supports any SPL token — not just a predefined list. This maximizes liquidity potential and expands user possibilities.
3. User Convenience
Web interface + Phantom/Backpack + no desktop client — the technical barrier to entry becomes minimal. A Solana user gets privacy in two clicks.
4. Security and Minimal Trust
The bridge uses a distributed FROST signature scheme (3-of-5) with geographically distributed signers. No single entity controls the bridge. This eliminates single points of control and reduces hack risks.
Economic bonds: each signer has 1000 ZEC locked (~$30,000). In case of an attack or malicious behavior, signers lose their bonds (slashing). Equivalence — 100% of bonds are burned. An attack becomes economically unprofitable.
5. Reserve Proof and Transparency
The bridge uses on-chain cryptographic proofs published on Solana every hour. Anyone can independently verify: locked = minted. This provides full auditability and reserve transparency.
6. Open Source and Community Governance
The project is MIT-licensed. The specification and F-PoC prototype are already published. Future transition to DAO governance will ensure transparency and community-driven development.
7. Redundant Infrastructure
No single point of failure:
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Clustered orchestrators with failover under 5 seconds;
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Multiple RPC providers (Helius, QuickNode, public endpoints).
Technical Features
| Component | What is used |
|---|---|
| Signatures | Distributed FROST signatures (3-of-5) |
| Storage on Solana | Escrow contract for secure token custody |
| Privacy on Zcash | Orchard protocol, zk-SNARKs (Halo 2) |
| Orchestrator | Fault-tolerant multi-node system |
| Reserve proof | On-chain cryptographic proofs (every hour) |
Speed of Operations
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Shielding (Solana → Zcash): ~30 seconds
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Unshielding (Zcash → Solana): ~10 minutes (due to Zcash confirmation time)
Conclusion
ZecShield can significantly expand Zcash’s capabilities and appeal, bringing liquidity and users from the Solana ecosystem while expanding the range of private assets.
This will increase Zcash’s relevance, improve its DeFi integration, and strengthen its position as a leading privacy blockchain.
ZecShield is the first bridge that:
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Makes Zcash a universal privacy layer for any digital asset;
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Opens access to $4 billion in Solana liquidity;
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Gives Solana users best-in-class privacy in two clicks via Phantom/Backpack.
Such a bridge will be an important step for the development and scaling of Zcash.
Questions?
I welcome community feedback and questions. Please comment below or reach out.
GitHub: andreudumitro-eng
Specification (Whitepaper): https://github.com/andreudumitro-eng/shield-bridge
Email: andreudumitro@gmail.com
Thank you for your consideration.
After publishing the initial application, I revised the roadmap toward a more conservative and reliable approach. I now propose to start with a simplified MVP to reduce technical risks and deliver a working prototype faster.
The project will now begin with a minimal MVP architecture:
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Solana deposit contract
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User specifies a Zcash address at deposit time
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Off-chain relayer processes deposits and performs Zcash shielding
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Relayer confirms completion on Solana
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User Protection Mechanism (MVP)
To address relayer-related risks, the following protection mechanism is included in the MVP:
Risk:
The relayer acts as a single point of failure. If it becomes unavailable or fails to process a request, user funds could become temporarily locked.Solution:
The Solana escrow contract includes a time-delayed refund mechanism.Mechanism:
• Each deposit records a timestamp and a user refund address
• If the relayer does not process the deposit within a predefined delay (refundDelay), the user can initiate a refund
• A grace period (gracePeriod) begins, allowing the relayer a final opportunity to complete the transfer
• If the relayer still fails to act, the user can reclaim their fundsResult:
The relayer cannot steal funds. At worst, it can only delay access to them for a limited and predefined time.All parameters are transparent and defined at the contract level.
This approach prioritizes user safety while maintaining implementation simplicity.
This initial version does not include a validator set or threshold cryptography (e.g., FROST). These components are planned for later phases — after the core system proves to work reliably.
This change is intentional: it allows us to validate the core bridge mechanism first, before adding additional complexity such as decentralization and advanced cryptography.
The long-term vision remains unchanged — to build a privacy bridge between Solana and Zcash — but the implementation will now follow a more incremental and verifiable path.
This approach improves deliverability, reduces technical risk, and ensures that meaningful progress can be demonstrated early in the development process.