Machine Identity

[Stephane Bortzmeyer <bortzmeyer at nic.fr>]

Sorry to (ab)use the patience of fellow IETFers but I'm puzzled for a
long time by an apparent gap in Internet protocols: there is no
standard of identity for machines on the Internet. 

I recently read a report about a P2P program which was difficult to
port to IPv6 because it used the IP address as the machine identity
and it was a problem to have several addresses (such as one in v4 and
one in v6).

The problem is that there is no obvious way to find the identity of
the machine. P2P programs typically require it because they base
things like reputation on it. Such an identity should be unique and
provable.

There are solutions for some protocols (SSH keys of RFC 4251 or Host
Identifiers of HIP in RFC 4423 are two good examples) but no general
"identity layer" in the Internet architecture.

Did I miss something? Is there work on it somwhere?