On Fri, Aug 11, 2006, ?????????????? ???????????? wrote: > Hello Stephen! > > Thank you *AGAIN* to the help! > I'm getting much fun with OpenSSL package. :D > > I could not figure out how I should use "openssl rsautl" on those > purely binary BIGNUMs that are used by Lynksys|Sipura in their > proprietary "MiniCertificate" standard. >
Well rsautl -verify and passing the public key and the signature buffer would do it. Probably with a -hexdump command too looking at the result below... > What I did is: > BN_mod_exp( result, original_sig, pub_exp, pub_mod, ctx); > > Hurray! > I got this as the "result": > 01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF \ > FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF \ > FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF \ > FFFFFFFFFFFFFF00A2A420DF49B17508946305979D24DD4040B8FA2C > > The lower digits are exactly the "sha1" hash of the concatenated > buffer with user name, expiry date etc. > (It all works this way only if I use the "RSA_F4" as the "public > exponent") > This hash seems padded. > > Now my question is - How is this padding called? > > I do think now, I must use not the "RSA_sign()" but the combination of > low-level functions like "RSA_private_encrypt()" with properly padded > hashes to them. > Or, as of my "gen-mc v0.91", I must put some "pad the hash" code > between the "EVP_DigestFinal_ex()" and the "RSA_sign()". > That padding is not standard and just includes the "raw" digest. Yes you are correct you can't use RSA_sign() for that. You should get that padding by feeding the digest into RSA_private_encrypt() with the RSA_PKCS1_PADDING type. Steve. -- Dr Stephen N. Henson. Email, S/MIME and PGP keys: see homepage OpenSSL project core developer and freelance consultant. Funding needed! Details on homepage. Homepage: http://www.drh-consultancy.demon.co.uk ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
