Question 1

How do I prove I created my artwork or photo before someone else claimed it?

Accepted Answer

The cryptographically defensible method is to anchor a SHA-256 hash of the file to a public blockchain before the work is published or shared. ProofAnchor does this by computing the hash locally (the file itself never uploads) and writing it to the Polygon blockchain, producing an immutable timestamp anyone can verify. This establishes that your specific file existed at a specific time, predating any later claim.

Question 2

Is copyright registration required for a blockchain timestamp to have legal weight?

Accepted Answer

No. Copyright exists automatically under US law the moment an original work is fixed in a tangible medium. Copyright registration is required to sue for statutory damages, but not to prove authorship or timing. A blockchain-anchored timestamp is independent evidence of when a specific file existed, which can strengthen a copyright claim whether or not the work is registered.

Question 3

Does ProofAnchor work for photos, music, video, and documents?

Accepted Answer

Yes, any file type. ProofAnchor anchors the SHA-256 hash of the file bytes, so the file format is irrelevant. It works identically for JPEG/RAW photos, WAV/MP3 music files, MP4/MOV video, PDF/DOCX documents, and source code.

Question 4

Does 'poor man's copyright', mailing yourself a sealed envelope, actually work?

Accepted Answer

No. The US Copyright Office has explicitly stated it offers no legal protection. The postmark binds to the envelope, not the contents, so the method cannot mathematically prove what was inside on a given date. A blockchain-anchored hash is different: the hash uniquely identifies the exact file bytes, and the on-chain record proves the hash existed at a specific time.

Question 5

Can I verify a ProofAnchor timestamp without trusting ProofAnchor?

Accepted Answer

Yes. The verify-proof Python package (pip install verify-proof) performs verification offline by hashing the file locally and comparing it against the on-chain record directly. ProofAnchor's servers are never involved in verification, the proof is independently checkable against the Polygon blockchain by anyone.

Question 6

How is this different from watermarking or EXIF metadata?

Accepted Answer

Watermarks and EXIF data live inside the file, so they can be modified, stripped, or re-embedded by anyone with access to the file. A blockchain anchor is external: the SHA-256 hash is recorded on a public ledger independent of the file itself. Alter the file in any way and the hash no longer matches the on-chain record.

Prove your file existed first

How It Works

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