The module implemented access authorization to servers, virtual hosts, or directories when incoming requests' HTTP OpenPGP signatures are valid and known by the local keyring.
The module also allowed for the signing and encryption of HTTP requests, providing increased data integrity and confidentiality.
Despite its innovative approach to HTTP request security, Mod_OpenPGP faced challenges due to the complexities of the OpenPGP standard.
This resulted in the concept of signed/encrypted HTTP request enhancements sometimes falling behind other methodologies in terms of adoption and usability.
[1] Enigform was mentioned in a worldwide survey of encryption products conducted by Bruce Schneier, K. Seidel, and S. Vijayakumar, highlighting its role in addressing data security challenges.