Re: [therightkey] algorithm blacklisting

[Carl Wallace <[e-mail]>]

On 1/3/14, 12:37 PM, "Ralph Holz" <[e-mail]> wrote:

>Hi,
>
>>> Alternatively, pull the root cert from which MD5 signatures were
>>>issued.
>>> As the MD5 attack still had considerable cost (for the hobby blackhat,
>>> not a 3-letter agency), it was deemed that this must suffice for a
>>>while.
>> 
>> To make the discussion CT-compliant, having logs provide a list of
>> algorithms that are used by each CA would be a nice feature to enable
>> decisions like this.
>
>Although, in the case you mention, that would not help all that much.
>Fortunately, the days of MD5 in X.509 are over.

I imagine other algorithms will see a similar fate at some point.

>
>But in fact, I've been thinking for a while that an additional
>monitoring infrastructure would be a nice-to-have thing in addition to
>CT --- and, FWIW, also TACK --- I view both drafts as naturally
>complementing each other.

Yes, better monitoring tools would be very helpful.

>
>CT, for example, is not meant to address the issue of whether
>certificates have been deployed correctly (e.g. correct host). I think
>active scans are still worthwhile to collect such information.

Identifying types of metrics that are useful to draw from a CT collections
seems like a worthwhile exercise.  Improved awareness of how a CA is used
sits under many suggestions, such as yours above to remove root CAs that
have used MD5.   

>
>Ralph
>
>-- 
>Ralph Holz
>I8 - Network Architectures and Services
>Technische Universität München
>http://www.net.in.tum.de/de/mitarbeiter/holz/
>Phone [phone]
>PGP: A805 D19C E23E 6BBB E0C4  86DC 520E 0C83 69B0 03EF
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