PROVEYOU SAIDIT FIRST.
Commit to any prediction, hypothesis, or decision before the outcome — then reveal it later with mathematical proof you didn't cheat. Bitcoin-anchored. No trust required.
USE IT NOW.
Prove a message matches a commitment using only the receipt. The math runs entirely in your browser — no server, no internet, no trust required.
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Drop your .ots and .stamp.txt files to verify the Bitcoin timestamp independently — no trust in us required.
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Sign in and make a public commitment to appear here.
THREE STEPS.
ZERO TRUST.
Write your prediction, hypothesis, or decision. A cryptographic digest is generated in your browser — your secret key never leaves your device.
Publish your commitment ID publicly. It's completely unreadable — nobody can guess your message from the hash, no matter how many tries.
When you're ready, reveal your message and key. Anyone can verify — mathematically — that you wrote it before the outcome. The proof is permanent.
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.
DON'T TRUST US.
VERIFY EVERYTHING.
We cannot forge your commitments. We cannot change your timestamps. We cannot lie about when you committed — even if we wanted to. The math and Bitcoin make it impossible.
YOUR DEVICE
Your secret key is generated in your browser and never sent to our server. We store only the MAC — a mathematical fingerprint. Without your key, the message is permanently hidden.
IS BINDING
HMAC-SHA256 is a one-way function. Given a MAC, it is computationally impossible to find a different message that produces the same fingerprint.
PERMANENT
Every commitment is anchored to the Bitcoin blockchain via OpenTimestamps. Nobody controls it — not us, not you, not anyone.
- ✗ Read your message before you reveal it
- ✗ Change what you committed to
- ✗ Backdate or alter your timestamp
- ✗ Forge a commitment on your behalf
- ✗ Prevent you from verifying independently
- ✓ Store your public MAC and timestamp
- ✓ Submit your MAC to Bitcoin via OTS
- ✓ Verify your key matches on reveal
- ✓ Maintain the public wall
- ✓ Publish the cryptographic core for public audit
WHAT THIS
DOES & DOESN'T.
What this provides
What this does NOT provide
The cryptographic core is MIT-licensed and publicly auditable. Don't trust us — read the code.
View Source on GitHub →VERIFY WITHOUT
TRUSTING US.
Your .ots file is a cryptographic proof anchored in Bitcoin. You can verify it independently on opentimestamps.org or using the open-source OTS client — no account needed, no trust in us required.
.ORG
- Go to your profile and click ↓ .ots on any commitment
- Name and save the file to your computer
- Visit opentimestamps.org
- Drag and drop your .ots file onto the page
- It will show the Bitcoin block number and timestamp — independent of us
(ADVANCED)
ots verify yourfile.ots
The OTS client connects directly to Bitcoin nodes to verify the proof — completely independent of psicommit.com.