Proof of agreement

An agreement neither side can rewrite.

Agreement and blockchain proof.

TIPISTAMP takes your terms, has both parties sign them with their own key, and stamps the result into Bitcoin. No middleman holds the original — anyone can verify it, offline.

Start free See how it works
agreement · 767baf25complete
terms
It was agreed to accumulate provisional advances for the rent.
parties
luc · pierre
effective
2026-09-04
statement
767baf257d8d11…b610dd
sig A
ES256 ✓ pierre
sig B
ES256 ✓ luc
anchor
OpenTimestamps → Bitcoin · block 965,528
 
Verified against Bitcoin

Check it yourself — runs in your browser, no account, no install, nothing sent anywhere. (Or download the raw bundle for agreement-verify.php.)

The trust gap

A signed PDF proves almost nothing.

Either party can keep a different copy, backdate it, or lose it. When the dispute comes, it’s your word, their word, and two files that don’t match.

What breaks today

  • No shared original — just copies you each control.
  • “Signed” usually means a typed name or an image.
  • Nothing fixes when it was agreed.
  • Verifying means trusting whoever stored it.

What TIPISTAMP fixes

  • One canonical statement, hashed — both sides bound to the same bytes.
  • Real cryptographic signatures (ECDSA P-256), keys generated in the browser.
  • The completed agreement is stamped into a Bitcoin block.
  • Anyone verifies it offline — no account, no trust in us.

How it works

Three steps. Hold the whole thing in your head.

Pitch the tree

Write the terms and name the counterparty. TIPISTAMP freezes it into one canonical statement and fingerprints it with SHA-256.

Both parties sign

Each side signs the fingerprint with a private key that never leaves their browser. Two signatures, one statement, no repudiation.

Stamp the tip

The completed agreement’s hash is published into Bitcoin via OpenTimestamps. From then on the date and the content are fixed for everyone.

A worked example

Verified price lists between a wholesaler and a garage.

A parts wholesaler seals each weekly price file and has the garage countersign it. Months later a charge is disputed — both sides ask Bitcoin the same question and get the same answer. Settled without lawyers, without either side trusting the other’s records.

tipistamp prove BRK-4471 @ 2026-03-12 → list $48.20 · core $12.00 · statement e3b0c442… · anchored block #851,903 · VERIFIED

Seal your first agreement in a few minutes.

Free to start. No card. The proof you walk away with is yours forever.

Start free