title: Decode/extract smime.p7m file contents (email with embedded files) with OpenSSL?
body: <p>We have an old process (VBScript) that reads a common mailbox and processes certain emails into a database.</p>
  
  <p>New regulations have all messages with attachments now being digitally signed.</p>
  
  <p>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 <em>really</em> 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.</p>
  
  <p>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.</p>
  
  <p>What am I missing?  Thanks in advance.</p>