Error while parsing CAdES-XL signature

[erny]

Some CAdES signatures may not me parsed using pkcs7_parse. Probably, the models are not correct. CAdES EPES specify a explicit signing policy, attribute that may no be available in current models.

We have to check the current ASN.1 models for advanced signatures.

This document: https://www.eldos.com/security/articles/7031.php?page=all#
is very good at explaining CAdES structures / alternatives and references RFC.