An apparatus to be used as at least part of a host, the apparatus comprising: means for enabling isolated determination operations, the means for enabling isolated determination operations to be comprised, at least in part, in the host, the host including at least one host central processing unit, CPU, to execute, at least in part, at least one host operating system, OS, the means for enabling isolated determination operations being capable of performing isolated determination operations in isolation both from interference from and control by the at least one host CPU and the at least one host OS, the isolated determination operations comprising: a user authorization determination that is performed in response, at least in part, to indication of physical presence of at least one user in proximity to the host, the user authorization determination being to determine, at least in part, whether the at least one user is authorized to issue at least one command to a trusted platform module, TPM, of the host; and a user presence determination to determine, at least in part, whether, after the indication has been provided, the physical presence of the at least one user in the proximity to the host has ceased; and wherein the means for enabling isolated determination operations is configured to store, at least in part, user authentication information and user privilege information in a manner that is inaccessible to the at least one host OS and at least one host CPU; wherein the user authorization determination comprises a user authentication determination that is based at least in part upon whether the user authentication information matches, at least in part, other user-associated information provided in response, at least in part, to at least one challenge presented by the means for enabling isolated determination operations; wherein the means for enabling isolated determination operations is to determine that the at least one user is authorized to use, at least in part, the host, and after this determination, determine whether the at least one user is authorized to issue the at least one command to the TPM based at least in part upon the user privilege information; and wherein the means for enabling isolated determination operations is configured to perform the user authorization determination, including the user authentication determination, in isolation both from interference from and control by the at least one host CPU and the at least one host OS. means for enabling isolated determination operations, the means for enabling isolated determination operations to be comprised, at least in part, in the host, the host including at least one host central processing unit, CPU, to execute, at least in part, at least one host operating system, OS, the means for enabling isolated determination operations being capable of performing isolated determination operations in isolation both from interference from and control by the at least one host CPU and the at least one host OS, the isolated determination operations comprising: a user authorization determination that is performed in response, at least in part, to indication of physical presence of at least one user in proximity to the host, the user authorization determination being to determine, at least in part, whether the at least one user is authorized to issue at least one command to a trusted platform module, TPM, of the host; and a user presence determination to determine, at least in part, whether, after the indication has been provided, the physical presence of the at least one user in the proximity to the host has ceased; and a user authorization determination that is performed in response, at least in part, to indication of physical presence of at least one user in proximity to the host, the user authorization determination being to determine, at least in part, whether the at least one user is authorized to issue at least one command to a trusted platform module, TPM, of the host; and a user presence determination to determine, at least in part, whether, after the indication has been provided, the physical presence of the at least one user in the proximity to the host has ceased; and wherein the means for enabling isolated determination operations is configured to store, at least in part, user authentication information and user privilege information in a manner that is inaccessible to the at least one host OS and at least one host CPU; wherein the user authorization determination comprises a user authentication determination that is based at least in part upon whether the user authentication information matches, at least in part, other user-associated information provided in response, at least in part, to at least one challenge presented by the means for enabling isolated determination operations; wherein the means for enabling isolated determination operations is to determine that the at least one user is authorized to use, at least in part, the host, and after this determination, determine whether the at least one user is authorized to issue the at least one command to the TPM based at least in part upon the user privilege information; and wherein the means for enabling isolated determination operations is configured to perform the user authorization determination, including the user authentication determination, in isolation both from interference from and control by the at least one host CPU and the at least one host OS.