How to create and use your signing certificate
Your digital signing certificate is used to identify yourself in the electronic world. A digital certificate can be used in several software applications. For example, it could be used for access to secure servers, encrypting data, signing e-mails, and other functions.
There are several techniques for creating key-pairs and certificates. Each of the vendor's web sites below will describe their unique process for creating your keys and their free trials. For example, your organization may have a defined process for creating signing certificates.
The vendors listed below are examples of CA's that provide certificates. There is a free trial certificate provided by most of these vendors for your initial testing.
Your public key is packaged in a X.509 certificate. That certificate contains your identity and the identity of an external party that has witnessed your possession of the associated private key. This is an essential element in the trust model of your digital signature.
Comodo offers their Secure Email Certificates here.
Trustwave offers their Secure Email Digital IDs here.