On Thu, Dec 01, 2005, Venkata Sairam wrote: > Hi > > I am trying to parse a ASN format that has the following structure. > ASNSEQUENCE[C] = 3 elements > INTEGER = 0 > SEQUENCE[C] = 2 elements > OBJECT ID = SHA > NULL = null > SEQUENCE[C] = 1 elements > SEQUENCE[C] = 2 elements > INTEGER = 1 > OCTET STRING = 20 bytes: 98:F7:6A:06:E1... > > My input is der encoding of this structure. > > I am not sure how to correctly read all the elements inside a SEQUENCE. In > particular, I want to read the digest and the digest algorithm. > I tried using the method ASN1_seq_unpack_ASN1_TYPE. Can anyone provide > sample codes or provide an explanation on how to parse? >
The easiest thing to do is to write an ASN1 module for the data. There are examples of varying complexity all over OpenSSL. Do a grep for ASN1_SEQUENCE in the source. Some of that structure looks like it uses some standard structures. For example the second SEQUENCE looks like a DigestAlgorithmIdentifier which is the type X509_ALGOR in OpenSSL. 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]
