Extract signing certs from a PKCS7 SignedData structure with m2crypto

I am trying to use M2Crypto to extract the signing certificates from a Windows PE file. According to the MS specification the data is stored in a PKCS#7 SignedData structure (sto开发者_如何学Cred in ASN.1 format, not the base64). I can't seem to get the binary format to load since it is not in PEM.

Pardon my ignorance with the crypto suites involved here, but if someone can show me the basics of how to get the signing certs out of a SignedData block I'd be most thankful!

If it helps, i found another solution for my problem but it is in C... how to Read the certificates file from the PKCS7.p7b certificate file usind openssl? If i could convert that to m2crpyto i'd be set.

---

I think there's more to this than just reading the certificate in PKCS7, unless you know absolutely what the offset & struct are.

You might want to take a look at either:

http://msdn.microsoft.com/en-us/library/aa380395(v=VS.85).aspx for the extraction process

Or possibly

http://msdn.microsoft.com/en-us/library/system.reflection.assemblyname.getpublickey%28VS.80%29.aspx

Additionally, it looks like Microsoft signs with a 'PFX' formatted file (I'd never heard of it before..)

But, I was able to find instructions on converting PFX back to a PEM, which should be a cakewalk to extract.

http://support.citrix.com/article/CTX106028