(I think this is more appropriate for openssl-users than -dev, so I'm 
responding to that list.)

On 10 Jul 2012, at 8:59 AM, Sirshendu Rakshit wrote:
> My questions are:
> 1) Is this a good way to know the EC_KEY using the curve-name Or there is
> some better way to know it?

If you're hardcoding a specific curve, you could presumably use the 
NID_secp224r1 (or SN_secp224r1, or OBJ_secp224r1) constants defined in the 
openssl headers.


> 2) When I tried "prime256v1" curve-name with the same RSA cipher it didn't
> work and I got handshake failure. Is there any relationship between ECDH*
> cipher used and the curve?

I don't think so, but it's possible that the client simply didn't support that 
curve? As I understand it, the client sends a list of curves it can accept in 
an optional ClientHello extension (rfc4492), and the server chooses a curve 
from among those and tells the client which one it chose. (Or, perhaps, it only 
negotiates the use of the ECDHE cipher suite if its chosen ephemeral key is 
based on a curve supported by the client.) The server can choose any curve that 
is acceptable to both it and the client; presumably the curve also needs to be 
large enough for DH exchange to generate a good session key. 



______________________________________________________________________
OpenSSL Project                                 http://www.openssl.org
Development Mailing List                       [email protected]
Automated List Manager                           [email protected]

Reply via email to