Thanks for the info. I have a follow-up question based
on my specific situation. The cipher suite I am
forcing the client and server to negotiate to is
EDH-RSA-DES-CBC3-SHA(I am also requiring sslv3). That
being the case, is not having true randomness on the
client a risk? How good is the randomization in
ssleay_rand_bytes in this particular case. I am using
openssl 0.9.4 on both client and server. It is
relatively easy to run an entropy gathering daemon and
upgrade the server side to 0.9.5 but considerably
harder to do the same on the client. Thanks for your
insights.
- Raghu
Dr Stephen N. Henson wrote:
raghuram belur wrote:
>
> Unfortunately, requesting input from the user is not
> an option for the application that I am working on.
> This is one of the reasons why I am trying to see if
> there is a way to "dumb down" the randomization on
the
> client and make it mostly a server side issue. I am
> interested in learning about the tradeoffs/risks in
> doing this.
>
That might cause problems, at least a naive
implementation with some SSL
and TLS cipher suites. The reason being that the only
part of an initial
SSL handshake with RSA cipher suites that is sent
encrypted is the
pre-master secret which is generated on the client.
An attacker who can predict the pre-master secret can
decrypt the whole
session.
Steve.
--
Dr Stephen N. Henson.
http://www.drh-consultancy.demon.co.uk/
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