On-chain proof of authorship

Seal your work. Prove it forever.

Put a permanent, tamper-proof seal on any paper, idea, creative work, or file. Thappa hashes it, pins it to IPFS, and mints an immutable on-chain record — proof of what you made, and when.

Minted on PolygonStored on IPFSNever alterable
Verified sealNo. 1428
Transformation-Invariant Provenance (preprint)
Papers & researchpublic
Content hash
0x9f2c4e7a…0a7f24
IPFS CID
bafybeigdy…...e4q
Polygon tx
0x3ad1...7…..77c4
Sealed at
Jun 8, 2026, 02:02 PM
Immutable · Polygonnever altered
≈2s
to seal
permanence
Polygon
settlement
IPFS
storage
How it works

Four steps to permanent proof.

You keep your work private if you want to. All that has to go public is a hash — a fingerprint that proves the work without revealing it.

01

Hash

Your content is fingerprinted with keccak256 — a 32-byte hash unique to those exact bytes. The work itself never has to be public.

02

Pin to IPFS

The file (or its metadata) is pinned to IPFS for permanent, content-addressed storage. Its CID is part of the record.

03

Mint the seal

An on-chain seal is minted on Polygon: owner, hash, type, and block timestamp. Duplicate-proof — one hash can be sealed only once.

04

Get your proof

You receive a stamped certificate and a public link. Anyone can verify it forever; no one — not even us — can alter it.

What you can seal

If it has bytes, you can seal it.

See use cases →
Researchers & academics

Papers & research

Manuscripts, preprints, datasets, and findings — sealed before you submit or share.

Founders & inventors

Ideas & specs

Concepts, product specs, business plans — proof you had it first, without revealing it.

Artists & creators

Creative work

Art, music, writing, designs — stamp authorship the moment you create.

Anyone

Any file

Contracts, code, audio, video — anything with bytes can be sealed.

Why it holds up

A seal you — and anyone — can trust.

Immutable

Once sealed, the record can never be edited or deleted. The contract is non-upgradeable.

Timestamped

The seal carries the block timestamp — cryptographic proof of when your work existed.

Duplicate-proof

A content hash can be sealed exactly once, so a seal is unambiguous ownership of that work.

Yours to verify

The seal is owned by your address and verifiable by anyone, with no account required.

Open verification

Hold a seal? Anyone can check it.

Paste a seal number, a content hash, or drop the original file. Thappa reads the chain and tells you who sealed it, and exactly when — no account, no trust required.

Verify a seal
Verified sealNo. 1426
Untitled No. 7 (oil on linen)
Creative workpublic
Content hash
0x7e3a1c8b…9a8451
IPFS CID
bafybeibq7…...t2c
Polygon tx
0x55fa...9…..9d3b
Sealed at
Jun 6, 2026, 06:15 PM
Immutable · Polygonnever altered

Stamp your work before you share it.

It takes seconds, and the proof lasts forever.