Browse Prior Art Database

Password Protection of Personal Computer Components

IP.com Disclosure Number: IPCOM000118658D
Original Publication Date: 1997-May-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Laffoley, B: AUTHOR

Abstract

Many components of personal computers, such as processors and SIMMS, are expensive and vulnerable to theft. Often a thief is deterred from stealing an entire machine because of its bulk, and removal of components is an attractive option. The solution described requires the planar to send an electronic password to the SIMMs and processor to make them operate normally. If the planar does not send the right password to the SIMMs, then the SIMMs do not work. Therefore, if the SIMMs are stolen and put into another planar, they will not work.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Password Protection of Personal Computer Components

      Many components of personal computers, such as processors and
SIMMS, are expensive and vulnerable to theft.  Often a thief is
deterred from stealing an entire machine because of its bulk, and
removal of components is an attractive option.  The solution
described requires the planar to send an electronic password to the
SIMMs and processor to make them operate normally.  If the planar
does not send the right password to the SIMMs, then the SIMMs do not
work.  Therefore, if the SIMMs are stolen and put into another
planar, they will not work.

      The SIMM is protected by a circuit, described below, that stops
power being applied to the memory chips on the SIMM until the right
serial code is sent to the circuit, thus preventing the use of the
SIMM.  When the correct code is sent to the SIMM, then the power is
applied and the SIMM would function normally.

      The serial password code is sent to the SIMM circuit after
power is applied to the motherboard but before the main reset had
been removed from the chips on the board.  Therefore, the SIMMs (and
Processor, if protected) work normally after reset is lifted (if the
right code had been applied to the password protected devices).  As
the unlocking of the protected devices is carried out before the
processor comes out of the reset state, normal boot procedures will
not be affected and no BIOS changes are required for the booting of
the system.

      One implementation is as follows:  A Lattice GAL6002 and serial
EEPROM are used to implement the password protection for the SIMM.
The binary password is stored in the EEPROM.  A state machine is
programmed into the GAL6002 to compare an incoming data stream with
the data stored  in the EEPROM.  If the two words are the same, then
the GAL6002 drives  FETs which allow power to be applied to the
memory...