But most importantly this would enable us to finally write JavaScript like this:

const a = prompt("how much is 31c in Fahrenheit")

The future looks bright!

The engineering challenge was: How do I prevent my future, lazy self from lying to the contract?

I tried to solve this by anchoring trust in three places:

1. Hardware-backed Proofs: The Android app reads from Health Connect (Galaxy Watch data) and signs a summary using a non-exportable key in the phone's TEE (Trusted Execution Environment). The smart contract verifies this signature on-chain.

2. Amnesiac APK Signing: To prevent myself from just "updating" the app to a version that fakes data, I sign the release with an ephemeral key and permanently delete the keystore. Since Android identity is tied to the signing key, I can’t overwrite the app without losing the hardware keys, which triggers an expensive on-chain penalty.

3. Permissionless Enforcement: The contract is "ownerless" regarding enforcement. If I fail a week, anyone can trigger the penalty function. The enforcer gets a small bounty, and the rest goes to charity (Giveth).

This is currently a 12-week experiment with ~$235 at stake. It’s not a product—it's a system design puzzle to see if I can make cheating more effort than just doing the workout.

Live Dashboard: http://fitvow.pedroaugusto.dev/

Source Code: https://github.com/pedrooaugusto/fitness-unbreakable-vow/

I’d love to hear your thoughts on the security model—especially how you’d try to 'break' the vow without actually exercising.

Comments URL: https://news.ycombinator.com/item?id=47139885

Points: 2

# Comments: 1

Write-up / architecture / threat model:

https://pedrooaugusto.github.io/blog/posts/making-missed-wor...

Current run parameters:

- Network: Arbitrum (Ethereum L2)

- Duration: 12 weeks (Jan 19 → Apr 13)

- Total stake: ~$235 (0.075 ETH)

- Penalty per failed week: ~$19 (0.00625 ETH)

How enforcement works:

- If a week fails, anyone can call enforceAgreement() and receive a share of the penalty; the rest goes to the Giveth charity.

- There’s also a Chainlink Automation backstop so “nobody enforced” can’t become an escape hatch. If automation is the first to enforce a missed week, there’s no caller to reward, so 100% of the fine goes to Giveth.

I’d love feedback on:

1) where you’d try to cheat this,

2) what would make it more verifiable/auditable to you.

Enforcement is permissionless: anyone can call the contract and a portion of the penalty is paid to the caller; the rest goes to a charity (Giveth).

Weekly activity data comes from my smartwatch (via Samsung Health / Health Connect), synced by an Android app that publishes the weekly activity on-chain.

The site is mostly a viewer for on-chain state. Full write-up / architecture / security notes in the first comment.

Comments URL: https://news.ycombinator.com/item?id=46780456

Points: 1

# Comments: 1

But I don't believe on that because Twitter is a billion dollar company and that kind of mistake is dumb. So idk.

> https://tabbyml.notion.site/Compensation-Sheet-ad61218889ab4...

Whenever ChatGPT uses something you wrote to answer a query they give you some cents based on how much content was stolen from you.

This would also encourage people to write more...

[1] https://github.com/tc39/proposal-type-annotations

In fact, they could release Google Prime and give us a lot of free products for a reasonable price .