Dear Dave, Thank you for your response!
On 2013-06-27 6:21, Dave Thompson wrote: >> From: owner-openssl-us...@openssl.org On Behalf Of Lukas Haase >> Sent: Tuesday, 25 June, 2013 19:13 > >> I have the public and the private key for ECDSA on secp128r1 in a file >> stored in PKCS8 format (saved with Crypto++; it is PKCS8 according to >> the Docu). >> >> I can create a signature without an error but unfortunately it is not >> validated successfully with my Crypto++ app: >> >> $ cat testakt.txt | openssl dgst -ecdsa-with-SHA1 -sign test.key >> -keyform DER >act.bin I think I found the problem but I am unsure how to deal with it :-( There are two ways to create a signature: The original message can be part of the signature (put=true) or not (put=false). In the first case, the signature gets larger (this is what I observe, the signature is not exactly 32 Bytes) and only the signature needs to be presented to the verifier. In the latter case, the concatenation message|signature needs to be presented [1]. I use put=false in my application because I aim for a signature as short as possible (used for product activation in my software). openssl dgst -sign unfortunately uses the put=true When I rewrite my software to accept put=true it works so I am sure that this is the issue. Is there an easy way to convert the openssl output to the second method by "stripping off" the data somehow, leaving *only* the signature? I looked at -sigopt but this does not provide an option for that. >> On the other hand, if I want to check a signature, I cannot even open >> the (public) key file: >> >> $ cat testakt.txt | openssl dgst -sha1 -verify activation.pub >> -signature act.bin >> unable to load key file >> > What exactly is in activation.pub? If it's a public-key-only > (aka public half, suitable for distribution), it can't be PKCS8; > the most common format for public is X.509 SubjectPublicKeyInfo, > which openssl calls PUBKEY. You are right, it is X509 [2]. > If that file is PUBKEY in PEM that command should work; if it is > PUBKEY in DER you need -keyform der; > [...] Yes, -keyform der was missing. Thank you! Regards, Luke [1] http://www.cryptopp.com/wiki/SignerFilter [2] http://www.cryptopp.com/wiki/Keys_and_Formats ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
