We have an old process (VBScript) that reads a common mailbox and processes certain emails into a database.
New regulations have all messages with attachments now being digitally signed.
The process now only extracts one file (smime.p7m). Using a GUI-based viewer, I can see the embedded files and extract them with no problem. However, what I really need is a command-line based extracter that will write out the embedded files (PDFs, DOCs, XLSs) – they’re not encrypted, just signed. I tested this by using a laptop that had no certificates and simply opened the smime.p7m file with the aforementioned viewer.
It looks like OpenSSL will decode/extract this and someone managed to get a version compiled on Windows. However, a lot of trial and error testing of the executable has been frustrating because I can’t find the right combination of flags to just say ‘open the smime.p7m file and write out all the embedded files you find’. ‘openssl smime’ always seems to want a ‘cert.pem’ after all the options and I haven’t got that.
What am I missing? Thanks in advance.
Looks like the only available option is to write a simple program using Chilkat’s library. This option costs $149 or $289, depending on what kind of license, per developer, but at least it’s royalty-free.