#67: Unknown password when importing a client certificate in Firefox

When installing a StartCom client certificate for Firefox, a box pops up with "Please enter the password that was used to encrypt this certificate backup". I tried my root password, admin password, a blank password, and Firefox Master Password to no effect. The certificate was not encrypted with a passphrase.

Wrong file format when importing the client certificate

So Firefox appears to require certificates that are in PKCS12 format (.p12) when importing. It cannot determine whether a client certificate file is encrypted, or if it is simply not a PKCS12 format file. My certificate, as downloaded from StartSSL, was in .cer format. Firefox would keep prompting for a password that doesn't exist.

The solution was to export the certificate in PKCS12 format, upon which point it was accepted by Firefox without triggering the password dialog. I was able to do format conversion via Keychain Access.app in OS X.


  1. Here's my problem. The original machine with the browser cert installed is gone. Stolen.

    Sigh! Any suggestions in this case?

    Thanks in advance.

    Om on August 19, 2012, 01:03 AM UTC

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