cTPM: A Cloud TPM for Cross-Device Trusted Applications

Current Trusted Platform Modules (TPMs) are ill-suited for use in mobile services because they hinder sharing data across multiple devices seamlessly, they lack access to a trusted real-time clock, and their non-volatile storage performs poorly. We present cloud TPM (cTPM), an extension of the TPM’s design, to address these problems. cTPM includes two features: a cloud seed shared between the TPM and the cloud, and remote storage in addition to the on-chip storage. cTPM allows the cloud to create and share TPM-protected keys across multiple devices, to manage a portion of a mobile device’s TPM storage, and to provide each TPM with a trusted real-time clock and with high-performance non-volatile storage.