diff --git a/windows/keep-secure/manage-tpm-lockout.md b/windows/keep-secure/manage-tpm-lockout.md index de41088ebb..d7b997538c 100644 --- a/windows/keep-secure/manage-tpm-lockout.md +++ b/windows/keep-secure/manage-tpm-lockout.md @@ -24,7 +24,7 @@ TPM ownership is taken upon first boot by Windows. By default, Windows does not In some cases, encryption keys are protected by a TPM by requiring a valid authorization value to access the key. A common example is configuring BitLocker Drive Encryption to use the TPM plus PIN key protector. In this scenario, the user must type the correct PIN during the boot process to access the volume encryption key protected by the TPM. To prevent malicious users or software from discovering authorization values, TPMs implement protection logic. The protection logic is designed to slow or stop responses from the TPM if it detects that an entity might be trying to guess authorization values. **TPM 1.2** -The industry standards from the Trusted Computing Group (TCG) specify that TPM manufacturers must implement some form of protection logic in TPM 1.2 and TPM 2.0 chips. TPM 1.2 devices implement different protection mechanisms and behavior. In general the TPM chip takes exponentially longer to respond if incorrect authorization values are sent to the TPM. Some TPM chips may not store failed attempts over time. Other TPM chips may store every failed attempt indefinitely. Therefore, some users may experience increasingly longer delays when they mistype an authorization value that is sent to the TPM. This can prevent them from using the TPM for a period of time. +The industry standards from the Trusted Computing Group (TCG) specify that TPM manufacturers must implement some form of protection logic in TPM 1.2 and TPM 2.0 chips. TPM 1.2 devices implement different protection mechanisms and behavior. In general, the TPM chip takes exponentially longer to respond if incorrect authorization values are sent to the TPM. Some TPM chips may not store failed attempts over time. Other TPM chips may store every failed attempt indefinitely. Therefore, some users may experience increasingly longer delays when they mistype an authorization value that is sent to the TPM. This can prevent them from using the TPM for a period of time. **TPM 2.0** TPM 2.0 devices have standardized lockout behavior which is configured by Windows. TPM 2.0 devices have a maximum count threshold and a healing time. Windows configures the maximum count to be 32 and the healing time to be 2 hours. This means that every continuous two hours of powered on operation without an event which increases the counter will cause the counter to decrease by 1.