Does a free general purpose ASN.1 Decode/Dump/Inspect program exist?

Question

Does a free general purpose ASN.1 Decode/Dump/Inspect program exist? I have a suspect ASN.1 block which may have failed decryption, and I would like to inspect it to see it it appears valid, and if so what elements it contains.

Answer 1

I also used dumpasn1 with good success for a couple of years), then I decided that looking at 200-lines long nested tags was a bit difficult to follow onscreen and wanted something more dynamic, so that I could collapse parts of the tree and stuff like that.

That's what I'm trying to create with my very own asn1js client-side javascript ASN.1 decoder. It's also opensource and uses dumpasn1's huge "known OIDs" config file. Doesn't try to detect all ASN.1 format errors, only the impossible-to-decode ones... (e.g. won't bother to differentiate DER from BER such as an INTEGER with extra leading zeros)

Yep, this is shameless self-promotion, but I hope you can find that software useful related to the problem you have in your question. ;-)

Answer 2

My favorite tool for ASN.1 viewing is Peter Gutmann's dumpasn1. Command-line only, but very flexible and gives diagnostics in case of errors.

Answer 3

This viewer utility is free, and seems quite good.

http://lipingshare.com/Asn1Editor/