On Sat, Jun 26, 1999 at 12:29:36AM +0200, Erwann ABALEA wrote:
> On Sat, 26 Jun 1999, Jason wrote:
>
> > Hi I am currently working on the SSLEAY crypto libraries and the Gemplus
> > GPK4000 cards. When I sign a message using SSLEAY md5() and
> > rsa_public_encrypt(), I get a signature string. However when I perform
> > the signature using GPK4000 I get a different string. Both return 64
> > bytes.
>
> First of all, please don't use SSLeay anymore, as the project has been
> renamed to OpenSSL (www.openssl.org). Eric Young is now working for RSA,
> and SSLeay is no longer maintained.
>
> Then... Are you sure the padding method used by the GPK4k is the same as
> the one used by SSLeay?
>
> > The keys which are loaded into the card were created by SSLEAY
> > rsageneratekey(). These keys are then stored into file in ASCII format
> > (0-F).These keys are then converted into a binary string and loaded into
> > the card.
>
> Are you sure the key components are correct for the GPK4k (this card has
> some constraints for the key parameters).
The format required to private load keys into the GPK is pretty bizarre.
This is probably where the problem is.
> > BTW. The plain text message before digest is 6 bytes (012345). I assume
> > padding is done automatically by the SSLeay MD5 functions.
> > RSAprivatencrypt uses PCKS-1 padding.
MD5() should return a 16 byte value. This is then padded with PKCS#1 padding
(block type, pad bytes, ASN.1 BER, hash) by the GPK before RSA encryption.
The GPK4000 will do PKCS#1 padding for you. It will do the correct
padding for MD5, SHA1, and SSL (MD5&SHA1) hashing. However if I
remember right, you must send the correct number of bytes. That's
how it tells which hash you're feeding it.
Also, are you sure that you're using the same PKCS#1? The GPK
uses v1.5 but there is a new v2.0 standard out since last summer, which
is very different and is based on the OAEP padding scheme to prevent
adaptive ciphertext attack. I haven't looked at newer SSLeay
but there is a chance that they put that in.
--
Eric Murray N*Able Technologies www.nabletech.com
(email: ericm at the sites lne.com or nabletech.com) PGP keyid:E03F65E5
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