[Cryptography] TB2F CAs as (un)official browser policy

Paul Hoffman paul.hoffman at vpnc.org
Thu Mar 19 13:20:17 EDT 2015

On Mar 19, 2015, at 4:13 AM, Peter Gutmann <pgut001 at cs.auckland.ac.nz> wrote:
> An interesting discussion is currently occurring on the Mozilla security
> policy list.  It seems a CA is late in filing an acceptable audit statement
> (the sort in which Ernst and Young said DigiCert was OK, WebTrust said
> TrustWave was OK, PWC said DigiNotar was OK, and so on).  The deciding factor
> on pulling the CA's cert is:
>  Richard Barnes has verified that there's minimal compatibility impact to
>  removing this root certificate. Current telemetry shows that this root has
>  been responsible for 9.57k out of 9.4B validations, or about one in a
>  million.
> OTOH if you're TB2F and get 0wned by Iranian hackers (Comodo, not DigiNotar,
> who weren't TB2F) then nothing happens.  So alongside DigiNotar's cert count,
> we now have another lower bound for the browser vendors' TB2F criteria, 10K
> certs issued isn't enough.

Careful there. The quoted paragraph was not about number of certs issued, but about number of validations using however many issued certs there were.

--Paul Hoffman

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