We present the design and implementation of a system thatenables trusted computing for an unlimited numberof virtual machines on a single hardware platform.To this end, we virtualized the Trusted Platform Module(TPM). As a result, the TPM’s secure storage and cryptographicfunctions are available to operating systems andapplications running in virtual machines. Our new facilitysupports higher-level services for establishing trust invirtualized environments, for example remote attestationof software integrity.