The Encryption module does mention PGP for fileDocuments
Encrypt does more than mention it. It uses it. If you look at its content, there is a lot of PGP-stuff:
FYI, we noticed that signing documents using PGP wasn't working as expected and raised a ticket with Mendix Support. This is their response:
Thank you for your patience. In their investigation, our internal team has established that signing PGP documents was never officially supported (although the documentation and annotations suggested otherwise). Apologies for this inconvenience and all the confusion it might have caused, it seems to be a relic of the past that was never truly fleshed out. To solve this, the "SigningCertificate" parameter of the PGPEncryptDocument Java action and the "SigningPrivateKey_Optional" parameter of the Encrypt_Document microflow have been removed.
The Encryption v2.4.0 release notes show that Mendix removed the possibility to sign PGP documents. Am just mentioning this in case someone else is beating his/her head against a keyboard, because signing documents isn't working ;)