A Digi-Token™ is any cryptographic USB token that has been tested and approved to work with Digi-CA™ [3]. And because most modern computers have a USB port, USB tokens are probably the most convenient hardware for storing a user's digital certificate/signature.
In high security environments, at least one Hardware Security Module [HSM] should be present. The following HSM devices are approved to work with Digi-CA™ [3]: