Everything you Never Wanted to Know about PKI but were Forced to Find
Out, by Peter Gutmann: http://www.cs.auckland.ac.nz/~pgut001/pubs/pkitutorial.pdf
Also, this, by the same person: X.509 Style Guide
Takes me back to debugging OSI stacks for BT using a 409 and the days when I used to quote my phone number (and my telex number) on my CV as an x121 address ( form 1 variant 3 )
I wonder for how many years in the future people will still have to fire up their HaskOCamlCoqda 10.4 ASN.1 library to deserialize EBCDIC over an ancient (gasp, wired!) serial port...
and don't get me started on the bodged stack from sprint which blindly ignored the spec!
I do have some less than fond memories staring and BER encoded SMS messages in Wireshark, however...
Well, technically, no. ASN.1 is a way to define messages and multiple representations for them.
It would be possible, I believe, to describe an Internet Protocol message and there might exist an encoding that would allow you to read and write IP packets, but the first is likely not easy and the second is definitely not standard.
Here's a description of the fun I had a while back attempting to talk to an Active Directory server using AD's variant of LDAP (which is an import from the ISO OSI stack and uses ASN.1):
Almost everything running SNMP had remote pre-auth vulns and on multiple levels - on the ASN.1 encoding side plus on the levels above that. And most of the SNMP managed gear was things like routers and switches and printers that were a nightmare to upgrade, or even exhaustively enumerate in your network.