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Re: CGA Use with HBA in Shim6 IETF Meeting July 10, 2006
Hi Iljitsch,
El 19/07/2006, a las 15:30, Iljitsch van Beijnum escribió:
On 19-jul-2006, at 11:57, marcelo bagnulo braun wrote:
As i understand it, the only way to make the shim6 security based on
IPSec is to assume that a global PKI is deployed, including client
certificates (i.e. not only server certificates) so that it is
possible to secure any-to-any communication.
From what i understand such global pki is not in place yet and it
doesn't looks like it will be anytime soon if ever. So, i really
don't think it is reasonable to build the security on the shim6
relying on such global pki deployment
does anybody think that it would be acceptable to build the shim6
security based on the assumption of a global PKI deployment?
Note that server certificates are relatively widespread, hence my
suggestion to adopt TLS as an alternative security mechanism in
addition to HBA.
server certificate are more widely used than client certificates
indeed, but in the case of the shim6 we need certificates for both
ends, so what do we do for securing the client?
besides, currently deployed certificates provide binding between FQDNs
and public key.... while in the shim6 we need binding between IP
addresses and public keys, meaning than currently deployed certificates
are not good (at least not in the general case and additional
assumptions about the existance of a FQDN is needed and the associated
implications...)
in addition, using certificates and public key crypto is much more
expensive than CGAs, since they would involve public key operations not
only for the validation of the locator set (as in CGA) but also for the
validation of the certificates themselves (and this costs grows if the
certification chain is long). In addition, there is the overhead due to
the transmission of the certificates in the protocol itself, including
all the certificates in the cert chain, which may even not fit in a
single packet so we may end up neededing to send multi-packet messages.
and all this for every shimmed communication....
i thought that one of the key goals in the shim6 design was
efficiency.... such an approach would really move us apart from the
efficiency path...
regards, marcelo
It would be helpful to determine whether we as a wg want this or not.
Obviously it's also possible to use IPsec rather than TLS but I don't
see how this would benefit us greatly and IPsec has proven hard to
deploy until now.