Installing a Code Signing Certificate

WARNING: if you are getting your code signing certificate from VeriSign or Thawte, DO NOT use a Windows Vista or Win7 computer to get your certificate. If you do, you will not be able to export the private key and so you won't be able to sign code on any other computer and you won't be able to back up your certificate. If this happens to you, Thawte will give you a free reissue (Thanks Thawte!) See https://www.thawte.com/ssl-digital-certificates/technical-support/ Make sure you do not use a Vista or Win7 computer for the reissue! [Added 7/13/2008]. View my earlier post to see why.

Every time I try and install a code signing certificate, I forget how I did it last time. You'd think that there would be a guide somewhere on how to do it, but if there is, I haven't found it. Both VeriSign and Thawte give tantalizing hints scattered among dozens of knowledgebase articles, but overall, it's rather poorly documented.

So here's how to do it: (Note: If you are using Comodo and saving to the CSP, you should skip to Step 3, then skip to Step 7. In this case, you don't use the PVK or SPC file.)

1. Prerequisites: You must have a PVK file and an SPC file. From VeriSign and Thawte, these are normally named mycert.spc and mykey.pvk. If you don't have both of these files, this article won't help you. You'll also need the password for the PVK file.
2. Install PVKIMPRT from Microsoft. You can download it here.
   
3. Remove your old certificate. If you are renewing an existing certificate, then keeping the old certificates installed isn't usually useful, and having multiple certificates will break SIGNTOOL if signtool is searching the certificate store. Go to Control Panel / Internet Options / Content, click Certificates, select your old certificate, and click Remove. The old certificate will probably be on the Personal page if you allowed PVKIMPRT to decide where to put it.
4. Import the certificate. Run PVKIMPRT to load the certificate into your cert store, like this (should all be entered on one line):
   
   C:\Windows\PVKIMPRT.EXE -import c:\mycert.spc c:\mykey.pvk
   
   You'll be prompted for your password, which you should already know. You'll also be asked which certificate store. You can let PVKIMPRT decide.
5. Verify the installation. Go to Control Panel / Internet Options / Content, click Certificates, select your old certificate, and click View in the bottom right. The certificate will probably be on the Personal page if you allowed PVKIMPRT to decide where to put it.
6. Install the intermediate certificate. When you view the certificate information, you'll probably get a message that says something like "Windows does not have enough information to verify this certificate."
Don't panic! This is easily solved by installing the intermediate certificate. For Thawte, download the Root Certificates. This package also contains the intermediate certificates. Extract the ZIP file. Double click the file named "Thawte Code Signing CA.cer". You should see the Certificate Information. Click Install Certificate. Now go back to the Certificates Page on Internet Options and view your certificate. You should see the complete Certificate Information.

Make sure you have the private key. Go back to the Certificates Page on Internet Options and view your certificate. At the end of the information, right under the "Valid from" dates, you should see something that says "You have a private key that corresponds to this certificate." If this isn't there, delete the certificate, and repeat this procedure starting from Step 3. This happened to me when the intermediate certificate wasn't installed.

Export the PFX file. The PFX file can be used by SIGNTOOL. One advantage is that PFX files can be created without a password, which is handy in automated builds if you are using SIGNTOOL. You can see the complete process with pretty pictures at PentaWare. Here's the abridged version:

1. Go back to the Certificates Page on Internet Options
2. Select your certificate
3. Click Export.
4. Click Next.
5. Select "Yes, export the private key."
6. Click Next.
7. Select "Personal Information Exchange - PKCS #12 (.PFX)." (If this option is grayed out, then your private key was not imported).
8. Check the box labeled "Include all certificates in the certification path if possible. THIS IS VERY IMPORTANT.
9. Click Next.
10. On Windows XP, you can leave the password information blank if you plan to use this PFX file for automated builds. On Windows Vista, you must provide a password.
11. Click Next.
12. Enter a filename.
13. Click Next.
14. Click Finish.

Sign your code! If you need some hints on this, see my earlier post.