BGP Security and PKI Hierarchies (was: Re: Wifi Security)
Steven M. Bellovin
smb at cs.columbia.edu
Thu Nov 24 01:44:42 UTC 2005
In message <20051124113104.0bd275d2 at garlic.apnic.net>, George Michaelson writes
:
>
>
>According to what I understand, there have to be two certificates per
>entity:
>
> one is the CA-bit enabled certificate, used to sign subsidiary
> certificates about resources being given to other people to use.
>
> the other is a self-signed NON-CA certificate, used to sign
> route assertions you are attesting to yourself: you make this
> cert using the CA cert you get from your logical parent.
>
Or your parent could have a CA and issue you two certs, one for signing
route assertions and one for signing certificates you issue to your
downstreams. That in turn has another interesting implication: an ISP
can *enforce* a contract that prohibits a downstream from reselling
connectivity, at least if the resold connectivity includes a BGP
announcement -- the ISP would simply decline to sign a CA certificate
for its customer, thereby depriving it of the ability to delegate
portions of its address space. (N.B. Certificates include usage
fields that say what the cert is good for.)
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb
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