SHA-256 of: "ISG#<issue id>|<headline>|<publication date>" followed, for each notice in the issue in ascending id order, by "|" and "<TYPE>:<title>:<body>" joined with "||" (UTF-8).

RFC 3161 timestamp granted 2026-10-07T12:00:54Z (serial 08fe9296) by freetsa.org — download the DER token and verify: openssl ts -verify -digest c6b5e93c7a96058759a305b6dd88689014f72a6f7931787097604d478842a23f -in issue-21.tsr -CAfile cacert.pem (CA: freetsa.org cacert.pem).

OpenTimestamps proof submitted to a public calendar — download the .ots proof; upgrade and verify with the ots client once a Bitcoin block confirms.

Wayback Machine capture: https://web.archive.org/web/20261007120058/https://internationalsacredgazette.org/archive/issue/21