1. A virtual TPM must provide the same usage model and TPM command set to an operating system running inside a virtual machine as a hardware TPM provides to an operating system running directly on a hardware platform.2. A strong association between a virtual machine and its virtual TPM must be maintained across the life cycle of virtual machines. This includes migration of virtual machines together with their associated virtual TPMs from one physicalmachine to another.3. A strong association between the virtual TPM and its underlying trusted computing base (TCB) must be maintained.4. A virtual TPM must be clearly distinguishable from a hardware TPM because of the different security properties of the two types of TPM.