### Terms and Conditions
- [x] I agree to the [Grant Agreement](https://9ba4718…c-5c73-47c3-a024-4fc4e5278803.usrfiles.com/ugd/9ba471_6ff6db4095fd4c4ba21babec361e927e.pdf) terms if funded
- [x] I agree to [Provide KYC information](https://9ba4718c-5c73-47c3-a024-4fc4e5278803.usrfiles.com/ugd/9ba471_7d9e73d16b584a61bae92282b208efc4.pdf) if funded above $50,000 USD
- [x] I agree to disclose conflicts of interest
- [x] 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.
- [x] 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](https://github.com/zcash/librustzcash/blob/main/CONTRIBUTING.md#styleguides) as a primary reference.
- [x] 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](https://github.com/zcash/librustzcash/blob/main/CONTRIBUTING.md#merge-workflow), [branch](https://github.com/zcash/librustzcash/blob/main/CONTRIBUTING.md#branch-history), [pull request](https://github.com/zcash/librustzcash/blob/main/CONTRIBUTING.md#pull-request-review), and [commit](https://github.com/zcash/librustzcash/blob/main/CONTRIBUTING.md#commit-messages) guidelines as exemplified in the librustzcash repository.
- [x] 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)
@aquietinvestor
### Organization or Individual Name
Jason McGee. I am recommending coinholders approve a bonus grant to Tachyon Foundation, the sole recipient, bringing their total for the Ironwood formal verification to $1,000,000. I am submitting this in my personal capacity as a coinholder; no funds go to me or to Shielded Labs, where I serve as Executive Director.
### Additional Team Members
```team-members.yaml
None. Tachyon Foundation did not request this nomination and had no role in preparing it. The team that performed the work is identified in the following application: https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50
```
### How did you learn about the Lockbox: Coinholder Retroactive Grants Program?
I helped create the Coinholder Retroactive Grants Program and helped administer its first rounds, and Shielded Labs is one of the keyholder organizations. This nomination was prompted by reading application #50 and concluding that Tachyon asked for too little.
### Requested Grant Amount (USD)
$261,058
### Category
Research & Development
### Project Summary
This is a bonus grant nomination, not a standard application. Tachyon Foundation applied for $738,942 in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50) for leading the formal verification of the Ironwood zk-SNARK. That application deliberately excludes real costs they absorbed and prices their emergency work at the bottom of the market band. I believe coinholders should recognize the full value of what they did. This application adds $261,058, bringing the total recognition for the Ironwood formal verification to an even $1,000,000.
### Project Description
This application was inspired by [Zooko's forum post](https://forum.zcashcommunity.com/t/retroactive-grant-application-give-bigger-grants-to-taylor-and-tachyon/57012) suggesting we should be able to nominate people for retroactive grants rather than waiting for them to apply, and that Tachyon and Taylor both asked for too little. I agree, and this application acts on it. Frank Braun also reached out to me separately to advocate for a bonus grant for both applicants, having come to the same conclusion on his own
The work itself is described in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50) and I won't restate it here. In short: after the Orchard counterfeiting vulnerability was disclosed in June 2026, Tachyon dropped everything, implemented the Ironwood circuit changes, funded two independent verification firms out of their own audit budget, and delivered a machine-checked Lean formalization of the Ironwood zk-SNARK verifier on the day of mainnet activation. Formal verification of a deployed cryptographic protocol is normally measured in years. They did it in under two months, against a fixed deadline, because the ecosystem needed it.
The reason for this application is what #50 leaves out. By their own accounting, Tachyon claims nothing for the two-month stall of their own roadmap, nothing for the burden on team members who carried Project Tachyon with reduced support during the pivot, no mobilization fee, and billing at the bottom of the emergency-response band. Those are real costs. They chose not to price them, which speaks well of them, but the community does not have to accept that discount.
There is also a strategic reason. The people who can do this work are rare. Zcash was lucky that a team with the right expertise, including a principal author of halo2, existed and was willing to act immediately with no guarantee of payment. Retroactive grants are the mechanism we have for making sure that kind of decisive action is rewarded, so that the people capable of it stay in this ecosystem and act just as decisively next time. Paying exactly cost for emergency work teaches the wrong lesson.
The amount is chosen simply: $738,942 plus $261,058 equals $1,000,000. I think a million dollars is a fair round number for work that resolved an existential question about the ZEC supply.
### Technical Approach (how you did it)
Not applicable. This application adds no new work. The technical approach is documented in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50) and in Tachyon's publications.
### Time Period of Work Completion
June 1, 2026 - July 28, 2026 (the same period as application #50)
### Total Budget (USD)
$261,058
### Budget Breakdown
Other: $261,058. Justification: a bonus to Tachyon Foundation in recognition of the unclaimed indirect costs and below-market pricing in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50), including the roughly two-month delay to their own roadmap, the burden on their team during the pivot, and emergency billing at the bottom of the market band with no mobilization fee. This application does not itemize those costs; #50 documents that they were incurred and not claimed. The figure is set so that total recognition for the work equals $1,000,000.
### Previous Funding
No
### Previous Funding Details
Not applicable
### Other Funding Sources
No
### Other Funding Sources Details
No funding source covers this bonus. Tachyon Foundation's own funding history is disclosed in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50).
### Success Metrics
The success metrics for the underlying work are in[ application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50): the machine-checked proof was published, Ironwood activated on schedule, and confidence in the ZEC supply was restored.
The success metric for this application is different: that coinholders affirm, on the record, that emergency work of this caliber is worth more than its billed cost, and that the people who protect Zcash are rewarded well.
### Proof of completion
All proof of completion is in [application #50](https://github.com/Financial-Privacy-Foundation/ZcashCoinholderGrantsProgram/issues/50): the public Lean formalization at github.com/zcash/ironwood, the merged circuit implementation in zcash/orchard#504, the published announcements, and the Ironwood mainnet activation on July 28, 2026.
### Conflict of Interest Disclosure
1. I am the Executive Director of Shielded Labs, one of the keyholder organizations of this grants program. I also helped create the program and helped administer its first rounds. I am submitting this nomination in my personal capacity, and no funds go to me or to Shielded Labs.
2. I provided a supporting statement for application #50, quoted in that application, in my capacity at Shielded Labs.
3. Shielded Labs worked alongside Tachyon Foundation, Valar Group, and ZODL on the Ironwood upgrade, and Ironwood originated as a Shielded Labs proposal. I have direct professional knowledge of the work described here.
4. Tachyon Foundation did not request, review, or contribute to this application. They may decline the funds if they wish.
5. I am a ZEC coinholder and participate in coinholder polls.
### Community Forum Posting
- [x] I understand it is my responsibility to post a link to this issue on the [Zcash Community Forums](https://forum.zcashcommunity.com/t/about-the-retroactive-grants-category/52106) after this application has been submitted so the community can give input. I understand this is required in order for the community to discuss and vote on this grant application. Note: If you are unable to post on the forum (for example, due to new user restrictions), please leave a comment below, and we will adjust your posting permissions.