Methods and systems for creating and managing certificates for gaming machines in a gaming network using a portable memory device. A gaming machine creates a certificate signing request which is stored on a portable memory device at the machine. Then, the memory device is coupled with an appropriate CA server. A certificate batch utility program on the server downloads and processes the CSRs. A certificate services program on the server issues gaming machine certificates according to the CSRs. In one embodiment, the certificates are uploaded onto the memory device, along with copies of certificate authority server certificates, including a root CA certificate. Then, the memory device is coupled with the gaming machine and software on the machine identifies and downloads its certificate based on the certificate file name.