Re: [TLS] draft on new TLS key exchange

["Dan Harkins" <[e-mail]>]

  Hi,

On Thu, October 6, 2011 4:22 pm, Philip Gladstone wrote:
> On 10/5/2011 2:12 AM, Dan Harkins wrote:
>>    Hi,
>>
>>    I just uploaded a -00 draft that defines a new key exchange
>> for TLS that does not require certificates-- authentication using
>> a simple password only. It can be found at:
>>
>>           http://tools.ietf.org/html/draft-harkins-tls-pwd-00
>>
>>    Please take a look. The authors solicit comments.
>>
>>
> There is a note in Security Considerations section that indicates that
> an active attack that tried a hundred thousand passwords would be easily
> detected. The problem is that, in many cases, finding the password of a
> single user is sufficient (and you don't care which user it is). This
> means that you iterate over all users, only trying a single password for
> each user. This is *much* more difficult to detect and stop. [It does
> assume that usernames are drawn from a small pool. This may well be the
> case for electricity meters where the username might well be the device
> serial number -- and these are in a small, consecutive, range]

  That's a great observation. It does suppose that for some given
password there is at least one user in the pool of usernames that has
that password. I'm not sure how true that is in general, but some text
in the security considerations on this is probably needed. Do you have
any?

  Dan.