Cryptographic Commitment Scheme

PROVEYOU SAIDIT FIRST.

Commit to any prediction, hypothesis, or decision before the outcome — then reveal it later with mathematical proof you didn't cheat. No blockchain. No trust required.

Make a Commitment → How it works
Algorithm
HMAC-SHA256
Dependencies
ZERO
License
MIT
Key Storage
CLIENT ONLY
Process

THREE STEPS.
ZERO TRUST.

01
Commit

Write your prediction, hypothesis, or decision. A cryptographic digest is generated in your browser — your secret key never leaves your device.

02
Wait

Publish your commitment ID publicly. It's completely unreadable — nobody can guess your message from the hash, no matter how many tries.

03
Reveal

When you're ready, reveal your message and key. Anyone can verify — mathematically — that you wrote it before the outcome. The proof is permanent.

Applications

WHO NEEDS
PROOF?

🔬

Researchers

Pre-register hypotheses without going through a journal. Prove your analysis wasn't shaped by results. Block p-hacking and HARKing before they start.

📈

Forecasters

Your Metaculus score is fine — but can you prove what you called to people who weren't on the platform? Build a portable, verifiable prediction record.

🏢

Executives & Teams

Seal strategic decisions before earnings calls, board meetings, or vendor negotiations. Cryptographic audit trail. No lawyers required.

🎲

Fair Games

Simultaneous sealed-bid auctions, game moves, or contest submissions. Commit first, reveal together. Mathematically fair by design.

Tool

USE IT NOW.

Your Commitment Receipt
⚠ SAVE THIS RECEIPT. Your secret key is not stored anywhere — not on this server, not in your browser. If you lose it, you can never prove this commitment. Copy or download it now.
Fields will fill automatically when you paste your receipt.
No public commitments yet.
Make a commitment and add it to the wall to appear here.
Transparency

WHAT THIS
DOES & DOESN'T.

What this provides

Cryptographic binding — you cannot change your message after committing
Cryptographic hiding — the commitment reveals nothing until you reveal
Domain separation — prevents cross-context replay attacks
Constant-time verification — immune to timing attacks
Zero-knowledge server — your secret never leaves your browser
HMAC-SHA256 — 256-bit security, same standard used by AWS and GitHub

What this does NOT provide

Anonymity — it doesn't hide who made the commitment
Forward secrecy — key compromise allows forging of that commitment
Byzantine fault tolerance — requires trust in the key holder
Permanent immutable record — without OTS anchoring, the timestamp is ours
Open Source

The cryptographic core is MIT-licensed and publicly auditable. Don't trust us — read the code. Built on pure Python with zero dependencies.

View Source on GitHub →