Using certificates with Mumble
Since the release of Mumble 1.2, users identify themselves with a certificate instead of a password. A certificate can be self-generated or issued by a third party organization. The certificate types Mumble differs between are
- Self generated (Not recommended)
- Class 1 for individuals, intended for email (The one most users should start out with)
- Class 2 for individuals or organizations, for which proof of identity is required (Recommended but not required)
The basic way of getting a certificate is to let Mumble auto create it upon install. If the user chooses to do that, and enters a valid e-mail address, it is possible to upgrade to a Class 1 or Class 2 certificate for the same e-mail address without the murmur server forgetting the user. In other words it is strongly recommended to use a valid and usable e-mail address even if you start out with a self generated certificate. A Class 1 certificate simply guarantees that the user has access to the e-mail address in the certificate, since the method of obtaining the certificate involves responding to a challenge sent to the e-mail address. A Class 2 certificate validates that the user is who he/she claims by validating real-life identification.
It is strongly adviced to get at least a free Class 1 certificate for use with mumble. A Class 2 certificate is recommended, but not required. At least Comodo  are offering free suitable certificates. There are step-by-step instructions for obtaining certificates and installing them in Mumble. Class 1 certificates generally have a one year validity. Before the certificate expires, it is adviced to get a new one for the same e-mail address. Mumble will warn the user 14 days before the certificate expires, so that a new one can be obtained. It is also possible to check the expiration date in the certificate wizard.
See this article for instructions on how to create a Comodo Class 1 certificate.
After obtaining a Class 1 or Class 2 certificate, this article, shows how to import it into Mumble.