Offline count-limited certificates

In this paper, we present the idea of offline count-limited certificates (or clics for short), and show how these can be implemented using minimal trusted hardware functionality already widely available today. Offline count-limited certificates are digital certificates that: (1) specify usage conditions that depend on irreversible counters, and (2) are used in a protocol that guarantees that any attempt to use them in violation of these usage conditions will be detected even if the user of the certificate and the verifying party have no contact at all with the outside world at the time of the transaction. Such certificates enable many interesting applications not possible with traditional (unlimited use) certificates, including count-limited delegation and access, offline commerce and trading using cashlike migratable certificates, and others. We show how all these applications can be made possible by using only a simple trusted timestamping device (TTD), which can in turn be implemen...

• Type: Journal
• Year: 2008
• Where: SAC
• Authors: Luis F. G. Sarmenta, Marten van Dijk, Jonathan Rhodes, Srinivas Devadas
• Keywords: Applied Computing, Certificates, Minimal Trusted Hardware, SAC 2008, Usage Conditions