Re: Preliminary results of using GPS to look for clock skew

[Dave Taht <dave.taht@gmail.com>]

On Thu, Sep 22, 2011 at 10:43 AM, Rick Jones <rick.jones2@hp.com> wrote:
> On 09/22/2011 10:34 AM, Dave Taht wrote:
>>
>> On Thu, Sep 22, 2011 at 10:15 AM, Rick Jones<rick.jones2@hp.com>  wrote:
>>>
>>>>
>>>> One thing that surprised me of late is
>>>> http://www.bufferbloat.net/issues/271
>>>>
>>>> while not related, surprises are the last thing we need as regards to
>>>> time.
>>>>
>>>
>>> The decision to stop letting networking contribute to entropy goes back a
>>> few years actually :)
>>
>> I wasn't paying attention then.
>>
>>> In another context, also where running-out of entropy was a problem,
>>> someone
>>> mentioned there are RNGs on USB keys that can be used to provide
>>> randomness/entropy/whatnot.  The one mentioned in that discussion was the
>>> "Entropy Key" from these folks: http://www.entropykey.co.uk/
>>
>> While I would like RNGs to be on-chip, the lack of randomness in a system
>> that supposedly does a lot of WPA encryption does concern me.
>>
>> https://dev.openwrt.org/ticket/9631
>>
>> Secondly, routers at least have multiple interfaces to get randomness from
>> which would be hard to spoof all at the same time.
>>
>> and wireless routers have more noise sources and interfaces...
>>
>> so while I find the decision to eliminate networking as a source of
>> randomness
>> makes some sense in a device with only one interface, I find it
>> indefensible to
>> have nearly no entropy pool at all as a result for devices with
>> multiple interfaces.
>
> I don't necessarily disagree, but there were a number of reasons given, many
> of which I believe are/were independent of the number of interfaces in the
> host.  I believe at least some of it can be found at
> http://lkml.indiana.edu/hypermail/linux/kernel/0805.3/0370.html  though I
> don't think it has the thread all the way back to its beginning.

These guys are on drugs, and it doesn't look like my point about multiple
interfaces was raised...

http://lkml.indiana.edu/hypermail/linux/kernel/0805.3/0383.html

"Nearby microwave ovens will add periodicy to the arrival of WLAN data."

Yep, that's your typical attacker, hauling a microwave oven around to
help me crack WPA...

What I want to know is how bad the decline in quality of urandom is
without random sources....


> rick
>



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Dave Täht
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