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Configure the level of TPM owner authorization information available to the operating system

This policy setting configures how much of the TPM owner authorization information is stored in the registry of the local computer. Depending on the amount of TPM owner authorization information stored locally the operating system and TPM-based applications can perform certain TPM actions which require TPM owner authorization without requiring the user to enter the TPM owner password. You can choose to have the operating system store either the full TPM owner authorization value the TPM administrative delegation blob plus the TPM user delegation blob or none. If you enable this policy setting Windows will store the TPM owner authorization in the registry of the local computer according to the operating system managed TPM authentication setting you choose. Choose the operating system managed TPM authentication setting of “Full” to store the full TPM owner authorization the TPM administrative delegation blob and the TPM user delegation blob in the local registry. This setting allows use of the TPM without requiring remote or external storage of the TPM owner authorization value. This setting is appropriate for scenarios which do not depend on preventing reset of the TPM’anti-hammering logic or changing the TPM owner authorization value. Some TPM-based applications may require this setting be changed before features which depend on the TPM’anti-hammering logic can be used. Choose the operating system managed TPM authentication setting of “Delegated” to store only the TPM administrative delegation blob and the TPM user delegation blob in the local registry. This setting is appropriate for use with TPM-based applications that depend on the TPM anti-hammering logic. External or remote storage of the full TPM owner authorization value for example by backing up the value to Active Directory Domain Services (AD DS) is recommended when using this setting. Choose the operating system managed TPM authentication setting of “None” for compatibility with previous operating systems and applications or for use with scenarios that require TPM owner authorization not be stored locally. Using this setting might cause issues with some TPM-based applications. If this policy setting is disabled or not configured and the “Turn on TPM backup to Active Directory Domain Services” policy setting is also disabled or not configured the default setting is to store the full TPM authorization value in the local registry. If this policy is disabled or not configured and the “Turn on TPM backup to Active Directory Domain Services” group policy setting is enabled then only the administrative delegation and the user delegation blobs are stored in the local registry. Note: If the operating system managed TPM authentication setting is changed from “Full” to “Delegated” the full TPM owner authorization value will be regenerated and any copies of the original TPM owner authorization value will be invalid. If you are backing up the TPM owner authorization value to AD DS the new owner authorization value will be automatically backed up to AD DS when it is changed.


Additional Information

  1. Registry path is:

    HKEY_LOCAL_MACHINE -> Software -> Policies -> Microsoft -> TPM # OSManagedAuthLevel

  2. The Administrative Template path is:

    System -> Trusted Platform Module Services

Notes

* Making mistakes while changing registry values can affect your system adversely. We recommend you to create a System Restore point before making registry manipulation. If you're new to Registry Editor, read this beginner's guide.
** To locate the registry and administrative template path, checkout beginner's guide.
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