Abstract: A multilevel infrared (IR) type security system prevents unauthorized use of a computer. A program resident on the computer implements a user-validation procedure. An IR key device carries a first serial number and an encryption key. A second serial number corresponds to a device internal to the computer. A mass storage device installed in the computer stores a validation record that includes an unencrypted portion and an encrypted portion, the unencrypted portion including a copy of the first serial number and the encrypted portion including a copy of said second serial number and a user personal identification number. The key device is coupled and interfaced with an infrared port on the computer by the user. The first serial number and the encryption key are read from the key device in order to gain authorized use of the computer. The key device may be decoupled from the computer after authorized use of the computer has been gained, and during operation of the computer.

Abstract: In an infrared (IR) type computer security system, each authorized user is provided with an IR key device that holds a serial number and an encryption key. A validation record stored on the computer's hard disk contains an unencrypted key device serial number and an encrypted hard disk serial number. The user couples the key device to an infrared port on the computer prior to power-up or reset. A program implements a user validation procedure. The procedure permits entry past a first security level if the key device serial number matches the unencrypted number in the validation record. If the first level validation is successful, the procedure then uses the encryption key to decrypt a second serial number found in the stored validation record. The procedure permits entry past a second security level if the validation record is properly decrypted and the second serial number matches the decrypted number. Failure in any step disallows use to the computer.

Abstract: A multi-level security system prevents unauthorized use of a computer. A program resident on the computer and implements a user-validation procedure. A key device carries a first serial number and an encryption key. A second serial number is stored in said computer, the second serial number being the serial number of a device internal to the computer. A mass storage device installed in said computer stores a validation record. The validation record comprises an unencrypted portion and an encrypted portion, the unencrypted portion including a copy of said first serial number and said encrypted portion including a copy of said second serial number and a user personal identification number. The key device is interfaced to the computer. The first serial number and the encryption key are read from said key device in order to gain authorized use of said computer. The key device may be removed from the computer after authorized use of the computer has been gained, and during operation of the computer.

Abstract: A computer security system is described. Each authorized user is provided with a key device that holds a serial number and an encryption key. A validation record stored on the computer's hard disk contains an unencrypted key device serial number and an encrypted hard disk serial number. The user connects the key device to the computer prior to power-up or reset. A program implements a user validation procedure. The procedure permits entry past a first security level if the key device serial number matches the unencrypted number in the validation record. If the first level validation is successful, the procedure then uses the encryption key to decrypt the hard drive serial number found in the stored validation record. The procedure permits entry past a second security level if the validation record is properly decrypted and the hard disk serial number matches the decrypted number. Failure in any step powers down the computer and renders it useless.