Hello Dave, What you said is right. Have checked ecs_ossl.c and implemented similar way to truncate the digest based on the order. Now, handshake is successful even for TLS1.2. Thanks alot. Rajeswari. On Mon, Feb 16, 2015 at 11:53 PM, Dave Thompson <dthompson at prinpay.com> wrote: > > From: openssl-users On Behalf Of Rajeswari K > > Sent: Friday, February 13, 2015 23:50 > > Hello Dave, > > Based on your input, have stopped calling i2d_ECDSA_SIG() > > and used BN_bn2bin() to overcome the der headers. > > And now, my verification is working fine. > > ECDSA_verify in ecs_vrf.c only uses i2d to *check* that the > input was canonical, to block certain possible attacks. It's > the d2i that parsed the signature, and the internal form > (ECDSA_SIG structure) is used for the actual verification. > > > Is there any function at openssl, to get the HASH used for > > the digest at ECDSA_verify()? > > I see that, for ECDSA_verify(), first argument is type. But > > when its calling the function pointer, ECDSA_verify() is not > > passing the type of the hash. > > So, would like to get the hash type from digest data. > > ECDSA (and DSA) signatures do not care about the hash > algorithm, only the length of the hash *value*. Notice > that ECDSA_verify does not pass type to ECDSA_do_verify, > which does the actual dispatch to a possible engine. > (This differs from RSA, at least PKCS#1 as used by SSL/TLS, > where the hash algorithm identifier is included in padding.) > > > I can understand that for TLS1.2, openssl uses SHA512. > > But the same information i would like to get from digest data. > > Is there any way to get this? Please share. > > For the ServerKeyExchange message (the case you said > you cared about) in TLS1.2, it appears OpenSSL server uses > the client's preference as stated in the sigalgs extension, > except in 1.0.2 a new SuiteB option forces SuiteB choices. > If the client offers all current hashes for ECDSA in strength > order, which is very reasonable, SHA512 will be the choice. > > > > _______________________________________________ > openssl-users mailing list > To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mta.openssl.org/pipermail/openssl-users/attachments/20150217/3dcbe06f/attachment.html>
