Re: [TLS] About encrypting SNI

[Yoav Nir <[e-mail]>]

On May 20, 2014, at 8:17 PM, Jacob Appelbaum <[e-mail]> wrote:

> On 4/25/14, Martin Rex <[e-mail]> wrote:
>> Russ Housley wrote:
>>>> I think Rich Salz has outlined very compelling reasons not to support
>>>> SNI.
>>> 
>>> While I might quibble with a detail here or there, I do agree with the
>>> conclusion.  If you need to protect SNI, then TOR or to a lesser extent
>>> TLS-in-TLS can be used.
>> 
>> I agree.  If you need TOR, you should use TOR.
>> 
> 
> This is curious - what specific property do you think you need from Tor?
> 
> To protect from information leaks in TLS or other protocols? If so,
> sure, use Tor.
> 
> One doesn't need the anonymity of Tor or the censorship circumvention
> of Tor per se - rather, this is basically compensating for a protocol
> that leaks plaintext information.

The requirement for encrypted SNI is very simple. I want to browse certain web sites such that if people knew I was browsing them it might get me in trouble. We all like the example of a gay teenager in Uganda, but it could just as well be an American browsing a website advocating Shari’a law for all western countries landing in a no-flight list.

Encrypting SNI would help if the “suspicious” web site is hosted by a hosting service, and there are multiple innocuous sites on the same IP address, and the traffic from the innocuous sites dominates the traffic to the server, and traffic for this site is not distinguishable by other means such as traffic analysis.  That’s a lot of ‘if’s up there, and if any of them fails, the adversary will know that I browsed the suspicious site. AFAIK Tor provides a far more robust protection of this kind of activity.

So I’m with Martin on this. If you need Tor, use Tor.

Yoav