Ideas and requirements for a novel signature distribution server

yarmo

In order for so-called signature profiles to work and be as easily discoverable as OpenPGP keys (related to https://community.keyoxide.org/d/17-shifting-to-signatures-as-primary-source-of-cryptographic-material/6), we need a novel signature distribution server.

Ideas and requirements for such a server:

Anyone can upload a signed text document of arbitrary data (clearsigned, text+signature of signature only).
Signatures from different protocols (OpenPGP, minisign, SSH, etc) are supported.
Signatures are assigned a random UUID upon uploading.
Signatures are automatically deleted after X months. Signed API requests can show a "sign of life" and delay the deletion of the signature.
Signatures can supersede previous signatures (not sure about implications).
Each cryptographic key can request a number of permanent UUIDs, which can be assigned to a signature (allowing them to accidentally perish but keep the old identifier).
Existing signatures can be removed using API requests signed by the key that uploaded them.
Uploaded signatures are limited in size.
Store signatures in the database using their hashed identifier.

Open issues:

Spam -> add a non-PII verification step to the upload process, IP throttling/bans?
What happens if signature contains PII of third party with regards to GDPR? -> Have a "request removal of signature" process?

omz13

Rather than novel, how about leveraging WKD but changing the paths in the queries from "openpgpkey" to "keyoxide" (or something appropriate), and instead of returning keys you get signatures.