The attic contains code and documentation about the trustify protocol, an alternative method for client webservers to request certificates from a server CA. Lets Encrypt does not plan to speak this protocol, though some of the things here may be of future use.
Notes on this code:
The Chocolate project to implement sweet automatic encryption for webservers.
There are two portions to the Chocolate protocol.
trustify/ contains code that can be run on any webserver (eventually, email, XMPP and other SSL-securable servers too); it is used to automatically request and install a CA-signed certificate for that server's public names.
server-ca/ contains a reference implementation for CAs to receive requests for certs, set challenges for the requesting servers to prove that they really control the names, and issue certificates.
Debian dependencies:
build deps: swig protobuf-compiler python-dev
others: gnutls-bin # for make cert requests python-protobuf python-dialog hashcash