
Often, 
heavy investments in systems or antiviral art firewall divert attention 
from the need to ensure proper physical security of equipment. 
People feel safe behind these systems and miss the most elementary precautions. 
 If it is difficult to get them used to lock their computer screens when
 they leave their desks, it is usually impossible to convince them to 
close and lock the door to leave the office even when you try to go one 
minute to the bathroom. 
However, even the exposure of a PC to a single minute without 
supervision may constitute a serious setback for the security of the 
system ...  For example, installing a hardware keylogger only requires 20 seconds of time. 
These keyloggers are sold as a way to back up what you type, but it is 
also true that pose a very simple way for an intruder to "damn" our 
keyboard. 
 
These devices are placed between the keyboard and plug the PC female from there capturing every keystroke you make. 
 Its small size and the fact that the keyboard connection usually left 
out of the user's view makes these devices to easily pass unnoticed.  Do you watch every day behind your PC tower to make sure you have not installed a keylogger?. 
It takes one careless user to install a keylogger and another to retrieve it.  Once this is done the owner of the keylogger can use a password to decrypt the contents of captured keystrokes. 
 This content can be really long as the memory of some keyloggers can 
reach up to 2 MB, more than enough to store the keystrokes of a victim 
the time period necessary to achieve all of your usernames and 
passwords. 
There are different models with different capabilities and functionalities.  The house Keyghost are models only for PS / 2 but have a wide variety of storage sizes to choose from.  The house KEYKatcher models include both PS / 2 to USB while it is true that lack of options with storage capacities between.  In both cases the price range between 100 and 300 dollars.
