[Freedombox-discuss] Tap-to-share PGP key exchange

Timur Mehrvarz timur.mehrvarz at googlemail.com
Fri Sep 30 14:09:53 UTC 2011


I provided this with my original post: http://timur.mobi/anymime-ksp/
Can you please phrase your concern relative to the fingerprint
verification example?

On 30.09.2011 15:50, Ted Smith wrote:
> So, how can a user verify that the key material comes from the expected
> peer? I know nothing of bluetooth and NFC, so instead of describing
> low-level protocols (which in most cases are NOT implemented using free
> software and CANNOT be naively trusted), please describe what I'd see
> using your app.
> 
> On Fri, 2011-09-30 at 13:46 +0200, Timur Mehrvarz wrote:
>> DKG, your impression that there is no security in place when using
>> Bluetooth and NFC is not true. Anymime uses encrypted and
>> authenticated communications only. And NFC does not just make the
>> procedure much more usable, it also removes the weakest spot with
>> "long range" Bluetooth: device discovery. What is needed now is that
>> people play with it and try to break it. And more devices with NFC
>> chips must become available.
>>
>> I will prepare another reply with more info, just need a bit more
>> time. My impression is, that those who specify and implement the lower
>> layers are honest about security. Also keep in mind that payment is
>> one important use case here. Why not benefit from the effort?
>>
>> I'm following this list long enough to be aware of the QR discussion.
>> I think both technologies need to be implemented for key exchange. If
>> someone comes to you with QR code printed on a business card, your NFC
>> chip won't help much.
>>
>> Thank you Stefano + Michael for your encouraging words.
>> Timur
>>
>> On 29.09.2011 17:45, Daniel Kahn Gillmor wrote:
>>> i'm concerned that bluetooth and NFC don't provide much protection
>>>  against spoofing.  that is, can the operator of a device using 
>>> these technologies verify that the communication comes from the 
>>> expected peer? or is it possible for a nearby attacker with
>>> control over the RF spectrum to inject messages into the
>>> communication?
>>>
>>> The advantage of the optical approach (QR codes and webcams) 
>>> discussed some months ago on this list (see posts about 
>>> "monkeysign" and "manus vexo") is that a (sighted) human user can 
>>> observe the communication between devices directly and ensure that 
>>> there is no tampering.
>>>
>>> Is there some mechanism with bluetooth or NFC that offers 
>>> equivalent protection from network interference?
>>>
>>> --dkg
>>>
> 
> 
> 
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