[Standards-JIG] certificate and private key retreival

Ian Paterson ian.paterson at clientside.co.uk
Tue Mar 16 20:13:26 UTC 2004


>> People should be able to use their private key from any client anywhere
on
>> the net. Each user's private keys can be safely stored and retrieved
>> (in-band over an insecure connection) from their own server (today via
>> jabber:iq:private), as long as it has been symmetrically encrypted with
(a
>> hash of) the user's password.

> Interesting idea, but of course one could not use
> the same password as the Jabber login.

In fact one could use the same password. But that would require a slight
(but fundamental) change to login policy...

We could specify that immediately after the user supplies the password, the
client must calculate its plain SHA-1 digest. The client then uses this
digest to login, as if it were the plaintext password. So non-SASL digest
authentication would be a digest of a digest.

This policy has the important advantage that the real password is *never*
communicated or stored anywhere. (I really don't understand why this is not
standard practice.)

With this policy, the user's real password could then be used to
symmetrically encrypt/decrypt their private key.

The transition to this login policy would be easy. For a while servers could
simply try to authenticate against both versions of the password. Once the
transition period is over (and the servers have carefully disposed of the
real passwords) they would no longer be able to authenticate legacy clients.




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