Thanks for ur help .
Can you guide me how can I use ECDH for exachnaging of the secret key. I have to implement in two phases. 1.i have private key of 256 bit lenght need to get phase i1 value wx,wy 2.In second I have phase1 value and private key and need to get secret key or public key. Thanks On 17 December 2012 13:55, Dave Thompson <dthomp...@prinpay.com> wrote: >> From: owner-openssl-us...@openssl.org On Behalf Of jeetendra gangele >> Sent: Monday, 17 December, 2012 02:48 > >> Yes i am talking about signature. >> ECDSA_SIG this ouptput structure will have r and s componet >> of 28 bytes each. [for 224-bit curve] >> So if I merge both r and s I will get 56 bytes right? >> These will not have any padding information?. >> > The struct points to two bignums, which use an internal > format; openssl can put what it likes in there. > If you get the (near-trivial) encoding as big-endian btyes > using BN_bn2bin, *that* does not have padding or overhead. > > Note that the numbers in an ECDSA signature are effectively > uniform random up to the field order, so they will *rarely* > be *smaller* than the keysize (here, less then 28 bytes). > If you want *fixed* 28 bytes each, *you* will need to pad. > > (I forgot to allow for this in my earlier reply. The ASN.1 > encoding can be less than 62 bytes in these cases.) > > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List openssl-users@openssl.org > Automated List Manager majord...@openssl.org ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
