[Cryptography] The next generation secure email solution

[Guido Witmond]

On 12/17/13 15:03, Ralf Senderek wrote:
> Guido Witmond wrote:
> 
>> You can use an untrusted CA to bootstrap. I show how it can be done at:
>>
>> http://eccentric-authentication.org/Brucon-Eccentric.pdf
> 
> This is an interesting idea, because it provides certificates on demand
> for ordinary users, if they decide to sign up to a certain site. The
> certs are then being used for other purposes, so the site does act as a
> bootstap for using crypto. The one thing that this proposal relies on is
> the availability of a common piece of software (user agent) that stores
> the private key for the user. It's this part of the picture where things
> get tricky.

Hi Ralf,

There is more to it than just a user agent.

Although, that user agent (and the web-site doing certificate signing)
is sufficient to create client certificates at that site if you are only
interacting with that site, for example a shopping site.

For email replacement you need to validate that there is no man in the
middle. The user agent cannot do that alone. It needs a global list of
certificates signed by each site. I call that the 'Global Registry of
Dishonesty' as it will show any attempts at a MitM.

When that is in place, user agents can verify there is no MitM after the
first roundtrip of messages. And when one endpoint detects a MitM, it
reports it at that registry for the world to know. After that the
certificates are validated. From this point on, the the end points (end
users) can bootstrap other communication channels, such as ZRTP, etc.

Regards, Guido.

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