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Physical Security 
If an attacker can physically access the computer hardware 
and
you use it after the attacker has 
physically accessed it, then TrueCrypt may become unable to secure data on the computer.
‡
This 
is because the attacker may modify the hardware or attach a malicious hardware component to it 
(such as a hardware keystroke logger) that will capture the password or encryption key (e.g., when 
you mount a TrueCrypt volume) or otherwise compromise the security of the computer. Therefore, 
*
Allegedly, for 1.5–35 seconds under normal operating temperatures (26–44 °C) and up to several hours when the 
memory modules are cooled (when the computer is running) to very low temperatures (e.g. –50 °C). New types of 
memory modules allegedly exhibit a much shorter decay time (e.g. 1.5–2.5 seconds) than older types (as of 2008). 
†
Before a key can be erased from RAM, the corresponding TrueCrypt volume must be dismounted. For non-system 
volumes, this does not cause any problems. However, as Microsoft currently does not provide any appropriate API for 
handling the final phase of the system shutdown process, paging files located on encrypted system volumes that are 
dismounted during the system shutdown process may still contain valid swapped-out memory pages (including portions 
of Windows system files). This could cause 'blue screen' errors. Therefore, to prevent 'blue screen' errors, TrueCrypt 
does not dismount encrypted system volumes and consequently cannot clear the master keys of the system volumes 
when the system is shut down or restarted. 
‡
In this section (
Physical Security
), the phrase “data on the computer” means data on internal and external storage 
devices/media (including removable devices and network drives) connected to the computer. 

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you must not use TrueCrypt on a computer that an attacker has physically accessed. Furthermore, 
you must ensure that TrueCrypt (including its device driver) is not running when the attacker 
physically accesses the computer. Additional information pertaining to hardware attacks where the 
attacker has direct physical access is contained in the section 
Unencrypted Data in RAM
. 
Furthermore, even if the attacker cannot physically access the computer hardware 
directly
, he or 
she may be able to breach the physical security of the computer by remotely intercepting and 
analyzing emanations from the computer hardware (including the monitor and cables). For 
example, intercepted emanations from the cable connecting the keyboard with the computer can 
reveal passwords you type. It is beyond the scope of this document to list all of the kinds of such 
attacks (sometimes called TEMPEST attacks) and all known ways to prevent them (such as 
shielding or radio jamming). You must prevent such attacks. It is solely your responsibility to do so. 
If you do not, TrueCrypt may become unable to secure data on the computer.