Re: [hybi] Frame size

[Ian Hickson <[e-mail]>]

On Mon, 19 Apr 2010, Thomson, Martin wrote:
> > >
> > > IF used for UTF-8 AND implementer counts characters instead of 
> > > octets THEN framing doesn't work. [...] One solution to this problem 
> > > is to start a frame with a known sequence of octets, so that this 
> > > can be detected.
> > 
> > That's an interesting approach, but I worry that anything hardcoded 
> > like this would be handled in ways that defeat the purpose.
> 
> You could complicate this if you like.  Perhaps each "fixed" sequence is 
> based on the output of a pseudorandom sequence, the seed to which is 
> assigned in the handshake.

Do you have any concrete suggestions for how we could do this? I'm not 
sure I follow.


> > This is why, for instance, the proposed handshake uses unpredictable 
> > keys to force the server to prove it read the handshake -- otherwise, 
> > servers written by amateurs might not actually read the handshake but 
> > just send back the right response, simply assuming the handshake came 
> > from a Web Socket server.
>
> [...] I'd like to better understand what this is buying though.*
> * ...just as I would like to understand the same for the handshake.

Assuming you are asking for a longer rationale for the current handshake, 
please search for "the rationale" in this message for an explanation:

   http://www.ietf.org/mail-archive/web/hybi/current/msg01607.html

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
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Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'