one of our application scenarios see section \[sec:Push\] is a mobile one. The concept for ticket system we present in section \[sec:TC-Tickets\] is in fact network agnostic and can be applied to the Internet as well the mobile world. Further mobile scenarios can be found in [@KuntzeSchmidt2006A; @KuntzeSchmidt2006C].

A TC-based Ticket System {#sec:TC-Tickets}
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The basic idea is to establish a (pseudonymous) ticket system using the identities embodied in the PCA-certified AIKs. Specific about our design is the tickets are generated locally on the (mobile) device of the user. Ticket acquisition an redemption rests solely on trusted computing methods implemented in the TPM chip embedded in the users platform. We first describe how AIKs can be turned into tickets that can be used in a ticket-based service access or identity management architecture, and then develop the processes for their acquisition and redemption.

AIKs as Tickets {#sec:AIKTickets}
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For security considerations the TPM restricts the usage of AIKs. It is not possible to use AIKs as signing keys for arbitrary data and in particular to establish tickets in that way. It is therefore necessary to employ an indirection using a TPM generated signing key and certify this key by signing it 