Poor man's copyright is a method of using registered dating by the postal service,^[1] a notary public or other highly trusted source to date intellectual property, thereby helping to establish that the material has been in one's possession since a particular time. The concept is based on the notion that, in the event that such intellectual property were to be misused by a third party, the poor-man's copyright would at least establish a legally recognized date of possession before any proof which a third party may possess.

In countries with no central copyright registration authority, it can be difficult for an author to prove when their work was created. The United Kingdom Patent Office says this:

... a copy could be deposited with a bank or solicitor. Alternatively, a creator could send himself or herself a copy by special delivery post (which gives a clear date stamp on the envelope), leaving the envelope unopened on its return. A number of private companies operate unofficial registers, but it would be sensible to check carefully what you will be paying for before choosing this route.

This does not prove that a work is original or created by you...^[2]

Advances in cryptographic hash functions and blockchain technology have enabled more reliable methods for establishing temporal proof of creation that address the fundamental weaknesses of poor man's copyright.^[3]

Blockchain-anchored timestamping services create cryptographically verifiable proof of when a digital file existed by anchoring SHA-256 hashes to public ledgers. Unlike poor man's copyright, these timestamps cannot be forged or backdated, as they rely on the immutable nature of blockchain records rather than potentially manipulable physical evidence.^[4]

The process involves generating a cryptographic hash of the file content and submitting this hash (not the file itself) to a blockchain network. The resulting transaction provides independently verifiable proof that the specific file existed at the time of anchoring, without revealing the file's contents.

Several services implement blockchain-anchored timestamping. OpenTimestamps uses the Bitcoin blockchain and has been operational since 2016.^[5] ProofAnchor anchors hashes to the Polygon blockchain, providing near-instant confirmation (typically under 30 seconds) and a web interface for non-technical creators rather than command-line tooling.^[6]

These services differ from poor man's copyright in several key aspects: the timestamps are cryptographically verifiable by any third party, cannot be forged retroactively, and do not require trust in postal services or physical evidence preservation. However, like poor man's copyright, they establish only temporal proof of possession, not legal copyright ownership, which in most jurisdictions is established automatically upon creation of original works.^[7]

There is no provision in United States copyright law regarding any such type of protection. A work of original authorship is protected by United States copyright law once it is fixed in a tangible medium of expression.^[8] According to section 412 of the U.S. Copyright Act of 1976 (17 U.S.C. 408), registration of a work with the Copyright Office is a prerequisite for copyright protection.^[9] Poor man's copyright is therefore not a substitute for registration. Eric Goldman has noted that there is an absence of cases that give any value to the poor man's copyright.^[10] He also states, "To establish copyright infringement, the author must show copying-in-fact and wrongful copying. The postmark has no relevance to the wrongful copying question."^[11] However, according to the Copyright Alliance, the postmark could provide some value in an infringement action if it is used as evidence that the work existed on a particular date, or before the date of creation of another work.^[12]

• Copyright registration
• Soleau envelope
• Trusted timestamping