WWW: http://www.fs.net/

SFS (Self-Certifying File System) is a secure, global file system
with completely decentralized control. SFS lets you access your
files from anywhere and share them with anyone, anywhere. Anyone
can set up an SFS server, and any user can access any server from
any client. SFS lets you share files across administrative realms
without involving administrators or certification authorities.

SFS names file systems by public keys. Every remote file server is
mounted on a self-certifying pathname -- a directory of the form
/sfs/LOCATION:HOSTID, where LOCATION is a DNS hostname and HOSTID
is a cryptographic hash of a public key. This naming scheme allows
for completely decentralized control -- anyone can create a file
server, and any user can access any file server from any client.
Various key management schemes can be built on top of SFS using
symbolic links to map human-readable names to self-certifying
pathnames.