On 05/04/15 23:42, Matt Caswell wrote: > > > On 05/04/15 22:04, David Rufino wrote: >> Hello, >> >> It's possible I'm doing something wrong here, but I can't seem to >> negotiate ecdhe with an elliptic curve other than P-256. To reproduce >> the issue, using openssl 1.0.2 >> >> openssl s_server -key server.key -cert server.crt -msg -debug -dhparam >> dhparam.pem -cipher ECDHE-RSA-AES128-SHA -tls1_2 >> >> gnutls-cli 127.0.0.1 -p 4433 -d 4 --insecure >> --priority="NORMAL:-KX-ALL:+ECDHE-RSA:-CURVE-ALL:+CURVE-SECP224R1" >> >> which gives the error >> >> :SSL routines:ssl3_get_client_hello:no shared cipher:s3_srvr.c:1366: >> >> changing to p256r1 succeeds. is there a particular why the negotation >> would fail with p224 ? my understanding is that openssl supports all the >> nist curves. > > > Try adding "-named_curve secp224r1" to your s_server arguments. This > specifies the curve to use for ECDHE keys. The default if you don't > specify a named curve is P-256 which is why it works when you are using > that curve. BTW, you can also use "-named_curve auto", which will just pick an appropriate curve. Matt
