On 10/11/2011 1:05, Invisible wrote:
> On 10/10/2011 06:04 PM, Darren New wrote:
>> On 10/10/2011 3:11, Invisible wrote:
>>> RC4? Man, how ancient is that? You realise it was a weakness in RC4 that
>>> allowed WEP to be broken, right?
>>
>> No. It was sending the key with each packet of data that allowed WEP to
>> be broken.
>
> Technically, it was
> 1. Restarting the keystream for each packet.
> 2. Using related keys for each packet.

Well, yes. Don't do that with a stream cipher.

> Probably. (Personally, I don't like stream ciphers, but anyway...)

Except that you have to turn a block cipher into a stream cipher if you want 
to encrypt a stream.

>> RC4 hasn't been broken if you don't restart the stream for every packet.
>
> RC4 has weaknesses concerning related keys. Also, the first few KB of the
> keystream is quite weak. Also, the keystream has certain statistical
> weaknesses. Also...

Yep. I'm not saying it's the best protocol. I'm saying it hasn't been broken 
wide open as you seemed to be implying.  If you know of someone who can 
break RC4 when properly used, please point me to it. Otherwise, I suspect 
the link between your computer and whatever computer you're managing is not 
going to get broken because of weaknesses in the RC4.

-- 
Darren New, San Diego CA, USA (PST)
   How come I never get only one kudo?

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