Computer key and computer lock system

• US 4,800,590 A
• Filed: 01/14/1985
• Issued: 01/24/1989
• Est. Priority Date: 01/14/1985
• Status: Expired due to Fees

• Current Assignee: William A. Higgins
• Original Assignee: William A. Higgins
• Inventors: Vaughan, James C.
• Primary Examiner(s): Cangialosi, Salvatore
• Application Number:
  US06/691,225
• Time in Patent Office: 1,471 Days
• Field of Search: 178/22.08, 178/22.09, 235/379, 235/380, 235/382, 235/487, 380/23-25, 380/46, 380/49, 340/825.34, 340/825.31
• US Class Current: 713/184
• CPC Class Codes: G06F 21/34 involving the use of external additional devices, e.g. dongles or smart cards
• CPC Class Codes: G06F 21/46 by designing passwords or checking the strength of passwords
• CPC Class Codes: G07C 9/215 the system having a variable access-code, e.g. varied as a function of time
• CPC Class Codes: G07C 9/33 by means of a password

Abstract

A computer access system includes a password generator (10) and an lock computer (50) connected to receive passwords generated by the password generator and grant access to a host computer (52) when a password from the password generator (10) matches a password separately generated by the lock computer (50). The password generator (10) and the lock computer (50) have corresponding pseudo-random number sequences stored in memories (26 and 90). The password generator (10) and the lock computer (50) have synchronized clocks (30 and 84), which define time intervals. During a given time interval, entry of a personal identification number in password generator (10) will cause the password generator (10) to generate a unique password from the random number sequence in memory (26) and time interval information from clock (30). The user transmits the so-generated password to the lock computer (50), which independently generates a comparison password from the corresponding pseudo-random number sequence stored in memory (90), and the time interval defined by clock (84). If the passwords match, access to computer (52) is granted by the lock computer (50). Since the valid passwords change with each time interval, subsequent use of an intercepted password will not grant access to the computer.

Claims

1. A system for remote access by a user to a computer, which comprises a plurality of password generators, each user having one of the password generators, an interface remotely accessible by the user and connected to said computer, means for loading equivalent information into one of the password generators and the interface for generation of the passwords, said interface and said password generators each including a clock, said interface and said password generators each including means for generating the same passwords from the equivalent information at corresponding clock time periods in said one password generator and said interface using the equivalent information and an input from said clock as data to generate the same passwords in said one password generator and said interface, with the passwords changing for each successive time period, said interface including means for comparing a transmitted password generated by said one password generator during the clock time period with a password generated by said interface during the clock time period, so that identity of the transmitted password generated by said one password generator during the clock time period with the password generated by said interface allows access to said computer through said interface, and for comparing the transmitted password generated by said password generator with the changed passwords generated by said interface for a plurality of adjacent time periods in the absence of identity between the compared passwords generated by said one password generator and said interface, to compensate for non-coincidence of the clock time periods of generation of the compared passwords.

2. The system of claim 1 in which said password generator includes a user entry means connected to supply a personal identification number to said password generator and said means for generating the passwords includes means for generating the passwords in response to entry of the personal identification number assigned to said password generator.

3. The system of claim 2 in which said means for generating the passwords generates an invalid password in response to entry of a personal identification number other than the personal identification number assigned to said password generator.

4. The system of claim 3 in which a pseudo-random number sequence and the clock time period are used by said password generator to generate the password, said password generator comparing the entered personal identification number with a stored personal identification number, said password generator generating the invalid password when the entered and the stored personal identification numbers fail to compare.

5. The system of claim 3 in which a pseudo-random number sequence, the clock time period and the entered personal identification number are used by said password generator and the pseudo-random number sequence, the clock time period and a stored personal identification number are used by said interface to generate the passwords.

6. The system of claim 2 in which said interface assigns an identification to the password generator into which the equivalent information is loaded and stores the password generator identification associated with the equivalent information in said interface, said interface retrieving the stored equivalent information in response to signal inputs corresponding to the password generator identification.

7. An interface unit for connection to a computer input for controlling access to the computer, which comprises means for receiving a signal input and for selectively supplying the signal input to said computer input, means for storing password generation information, means for generating passwords connected to receive the password generation information from said storage means, said password generating means being connected to receive an input password from said signal input means for comparison with a generated password, and a clock connected to supply a time input to said password generating means, said password generating means including means for generating a password from the information in said storage means and the time input using the information and the time input from said clock as data to generate the password, with the passwords changing for each successive time period, for comparison with an input password from said signal input means, said password generating means being connected to control said signal input means, so that coincidence of a generated password and an input password causes said password generating means to enable said input signal means to supply input signals to the computer, said interface unit including means for comparing the input password with the changed passwords generated by said interface unit for a plurality of adjacent time periods in the absence of identity between the generated and input passwords, to compensate for non-coincidence of clock time periods of generation of the input and generated passwords.

8. The interface unit of claim 7 additionally comprising a password generation information signal transmission means connected to receive the password generation information from said password generation means for transmission to a password generator.

9. The interface unit of claim 8 in which said interface unit assigns an identification to the password generator to which the password generation information is transmitted, and stores the password generator identification associated with the password generation information in said storage means, said interface unit retrieving the stored password generation information from said storage means in response to signal inputs at said signal input receiving means corresponding to the password generator identification.

10. The interface unit of claim 8 in which said password generation information signal transmission means includes means for transmitting the password generation information to the password generator optically.