We are requesting $88,000 for four months of Zcash firmware and app development, testing, internal security review, and 12 months of maintenance.
Progress and Remaining Work
Our first $50,000 grant delivered Zcash signing support, published firmware code, and Android integration. ZCG accepted the milestones and paid the grant. We reported transparent, Sapling, Orchard, and Ironwood support; Ironwood was added without additional funding.
Our Slint test build uses 98.8% of its available firmware flash region, leaving about 10 KB. Adding an empty horizontal layout pushes it over the limit. These are our build measurements for that region, not the device’s total physical flash.
We are developing hito-ui to address this constraint. It is public under MIT, with demos and build instructions, and is still a work in progress. We need to continue developing and testing it, move the Zcash screens to it, stabilize the firmware, and finish iOS integration.
Our September 30 passcode demo showed these preliminary results:
| Measurement | Slint build | New demo |
|---|---|---|
| Initial frame | 236 ms | 112 ms |
| Frames during first five character entries | 274-282 ms; one result per entry | 19-33 ms per frame; two per entry |
| Flash added by an empty horizontal layout | 23,364 bytes | 32 bytes |
These are our measurements, not a controlled or independently reproduced comparison. The new demo already had a horizontal layout. The numbers do not establish full input latency or whole-wallet memory savings; the complete Zcash flow still needs testing.
The first grant also covered UI, stabilization, documentation, and release work. We will agree with ZCG how the remaining work is funded, as explained in the application. The integration budget includes further UI development needed for Zcash, not payment for work already completed on Ironwood or hito-ui.
Why Four Months
A signing demo left us with performance and reliability work still to do. We propose two months for integration and two for testing, security review, fixes, and repeat tests. Testing continues throughout development.
Mikhail will handle firmware, iOS, and review coordination. Daniil will handle firmware, Android, and device testing. Both will work full-time. Herb Stephens is listed as Advisor and Denis Ivanov in Operations, as in the previous grant.
| Stage | Target | Work |
|---|---|---|
| M1 | November 30, 2026 | New-UI Ironwood signing and testnet broadcast on five production-representative devices; approval, rejection, errors, and performance tests |
| M2 | December 31, 2026 | Integrated Android/iOS candidate, transaction tests, and security-review scope |
| M3 | January-February 2027 | January testing and internal review; February fixes, repeat tests, final build checks, and release |
| M4-M15 | March 2027-February 2028 | Monthly maintenance and reports |
These dates assume funding starts November 1. They shift if funding or acceptance is delayed. Maintenance starts only after final release acceptance and lasts 12 months, provisionally through February 29, 2028.
Security and Testing
We will review the code manually and use V12 or similar tools. Tests will cover supported payments, repeated signing, memory use, malformed input, interrupted connections, upgrades, and recovery. The review covers signing, transaction validation, what the device displays, and relevant key, transport, UI, and update code.
We will record failures, findings, fixes, and test results. The other engineer will check fixes and reproduce the final unsigned firmware from clean build inputs, with matching hashes.
Release requires passing the required tests, resolving critical/high findings from our review, and documenting decisions on lower-severity issues. We will publish the report, delaying sensitive details until fixes are available.
This is internal review, not an independent audit. Physical attack testing and full mobile-app audits are excluded.
We have approached Least Authority as a prospective partner for a future independent security audit. Scope, terms, and funding still need to be agreed. This follow-up audit is outside the current request and is not required to complete this grant.
Budget and Payments
| Work | USD |
|---|---|
| Two months of integration | 30,000 |
| Two months of testing, internal review, fixes, and release | 30,000 |
| Security tools | 1,000 |
| Twelve months of maintenance | 27,000 |
| Total | 88,000 |
Payments are $15,000 at startup, $15,000 after M1, $16,000 after M2, and $15,000 at M3’s January review checkpoint. These advances fund upcoming work. The tool allowance is capped; we will report spending and reconcile unused funds under grant terms. Changes need agreement.
January’s checkpoint pays for February’s work. M3 is complete only after February’s release acceptance, with no further engineering payment then. These payment terms require ZCG agreement.
Maintenance is $2,250/month for six combined engineer-days covering small fixes, compatibility, testing, releases, and support. It is not unlimited or 24/7 support. Major upgrades, new integrations, independent audits, and manufacturing are outside this request; no partner distribution or Zodl integration is promised.
We will report progress, test results, delays, and spending monthly. Feedback on scope and funding is welcome.