Code Signing Certificates, Expiry Dates and Timestamping

When I set about signing a Java deployment rule set with a code signing certificate, I noticed that my certificate had an expiry date of 1 year from the current date.  My initial thoughts were that I didn’t want all these Java applications to suddenly stop working in a years time because my code signing certificate had expired!  But I needn’t have worried.

Why Do Code Signing Certificates Expire

When a code signing certificate expires, you can no longer sign any content with it.  The reason they expire is for security purposes.  If they didn’t ever expire and the certificate fell into the wrong hands, anybody could impersonate your company forever!

Will Signed Content Stop Working When My Certificate Expires?

If you haven’t added a timestamp during the signing process, the signed content will check the certificate expiration date against the current date and fail if the certificate has expired.

However adding a timestamp during the signing process provides verification that the signing took place when the certificate was valid, and your signed content will be valid indefinitely.  Timestamping is a mechanism that ensures your digital signature remains trusted long after your Code Signing certificate has expired.

Create a Code Signing Certificate using Active Directory Certificate Services

Ok, this post is shameless plagiarism from this post.  But I couldn’t risk losing sight of good content.  Thanks (and apologies) go to David Barrett!

Enable the Code Signing Certificate Template

  1. On the appropriate server (e.g. the CA root), open Certificate Services Manager.
  2. In the left pane, select Certificate Templates.
  3. Check for a Code Signing template – by default, this isn’t available.  If it isn’t, add it:
    1. From Action menu, select New -> Certificate Template to Issue.
    2. Select Code Signing, then click OK.

 Grant Permissions for User(s) to Create Code Signing Certificates

  1. From the Certificate Services Manager, right click Certificate Templates and select Manage.
  2. From the list of templates, right-click Code Signing and select Properties.
  3. Select the Security tab.
  4. Any users that should be allowed to create code signing certificates need to be granted Read and Enroll permissions, so add users and permissions as necessary.
  5. Apply changes.

Create a Code Signing Certificate

  1. On the development machine (logged in as a user who has been granted permissions to create a code signing certificate), open Microsoft Management Console.
  2. From File menu, select Add/Remove Snap-in…
  3. From Available snap-ins, select Certificates and then click Add.
  4. Select My user account, and then click Finish.
  5. OK out of the Add/Remove snap-in window.
  6. You will now see Certificates listed in the console view on the left.  Right-click Personal, select All Tasks, then Request New Certificate.
  7. Click Next on the first screen (Before You Begin).
  8. Click Next on the Select Certificate Enrolment Policy screen (Active Directory Enrolment Policy will be applied).
  9. In the Request Certificates screen, tick Code Signing, and then click Enrol.  A certificate will be created and placed in the user’s Personal store.