Cryptographic hardware tokens

[Marcelo Magno T. Sales]

Hi, people

I need to store a digital certificate in a hardware USB token and make it work 
with Fedora. The user must be able to use the certificate in the token to 
encrypt/decrypt files, sign e-mails and identify him/herself at secure sites 
which require client identification by digital certificate.
I don't have a clue on where to start. Has anyone here done that?

Thanks,

Marcelo