Postmark ((free)) Site

The postmark was invented by Henry Bishop, the Postmaster General of Great Britain, in 1661. Introduced at the London Chief Post Office, the "Bishop Mark" was a small, circular stamp divided into two sections. One half showed the month (expressed as a two-letter abbreviation), and the other half showed the day of the month.

As of early 2026, understanding the postmark is more critical than ever due to significant regulatory changes. 1. What is a Postmark? postmark

Using a combination of Public Key Infrastructure (PKI), digital signatures, and cryptographic hashing, an E-Postmark securely seals a digital file. It proves that a specific electronic document existed at a specific point in time and has not been altered by a single bit since its signature. Blockchain and Decentralized Timestamps The postmark was invented by Henry Bishop, the