Adam Back proposed [4] a simpler implementation of the Eternity Service, using the existing Usenet infrastructure to distribute the posted files all around the world.
To achieve anonymity in publishing, Eternity Usenet employs cypherpunks type I and type II (mixmaster) remailers as gateways from email to newsgroups. Publishers PGP-sign documents which they wish to publish into the system: these documents are formatted in html, and readers make http search or query requests to `Eternity Servers' which map these requests into NNTP commands either to a remote news server or a local news spool. With the initial implementation, the default list of newsgroups to read consists only of alt.anonymous.messages. The Eternity Server effectively provides an interface to a virtual web filesystem which posters populate via Usenet posts. Eternity Usenet uses normal Usenet mechanisms for retrieval, posting, and expiring, so publishers may not have control over the expiration time or propagation rate of their document.
Reader anonymity for Eternity USENET is provided when the system is used in "local proxy" mode, in which the user downloads the entire eternity newsgroup from a remote server. The server can still link the reader to that day's contents of an eternity newsgroup, so the reader anonymity is not as strong as we might like.
Back treats Usenet as an append-only file system. His system provides support for replacing files (virtual addresses) because newer posts signed with the same PGP key are assumed to be from the same publisher. Addresses are claimed on a first-come first-served basis, and PGP signatures provide linkability between an initial file at a given address and a revision of that file. It is not clear what happens when two addresses are claimed at once - since Usenet posts may arrive out of order, it would seem that there might be some subtle attacks against file coherency if two different Eternity Servers have a different notion of who owns a file.
While the system is not directly `censorable' as we usually consider it, the term `eternity' is misleading. Usenet posts expire based on age and size. Back does not provide an analysis of how long a given document will survive in the network. The task of making a feasible distributed store of Eternity documents is left as a future work.