Computer accessing system
First Claim
1. A system for accessing a computer by a user having an assigned password to establish a communications link for data transmission between a computer terminal and a computer, the system comprising access means at the terminal for sequentially generating a pseudorandom number of a first sequence of pseudorandom numbers, means receiving said pseudorandom number and said user assigned password and in response thereto modifying the pseudorandom number as a predetermined function of the password to provide an access code signal unique to itself, means transmitting the access code signal and identification signal from the terminal, controller means at said computer, the controller means receiving the transmitted access code signal and identification signal, the controller means including means responsive to the identification signal for sequentially generating a pseudorandom number of a second sequence of pseudorandom numbers congruent with the numbers of the first sequence and generating a signal corresponding to said user assigned password, and means for modifying said pseudorandom number of the second sequence with said last mentioned signal to provide a congruent access code signal and in response to the equality of the congruent access code signal and transmitted access code signal providing an access signal, and means receiving the access signal and in response thereto establishing a data transmission path between the terminal and the computer, said first and second sequences being the same, whereby computer access is secured through a sequential change of access codes in a pseudorandom fashion without direct transmission of said user'"'"'s password.
0 Assignments
0 Petitions
Accused Products
Abstract
A communications link between a computer and a remote user is effected by a portable access unit which generates a nonrecurring access code which is a function of a password and a pseudorandomly generated number. The access code is transmitted and compared with an access code generated by a computer access controller. In addition to the access code, the pseudorandomly generated number provides an encryption key which is not transmitted but corresponds to a mating encryption key generated at the controller. The mating encryption keys are utilized to set up data transmission enciphering/deciphering networks successive links are established by incremented pseudorandomly generated access codes.
-
Citations
20 Claims
- 1. A system for accessing a computer by a user having an assigned password to establish a communications link for data transmission between a computer terminal and a computer, the system comprising access means at the terminal for sequentially generating a pseudorandom number of a first sequence of pseudorandom numbers, means receiving said pseudorandom number and said user assigned password and in response thereto modifying the pseudorandom number as a predetermined function of the password to provide an access code signal unique to itself, means transmitting the access code signal and identification signal from the terminal, controller means at said computer, the controller means receiving the transmitted access code signal and identification signal, the controller means including means responsive to the identification signal for sequentially generating a pseudorandom number of a second sequence of pseudorandom numbers congruent with the numbers of the first sequence and generating a signal corresponding to said user assigned password, and means for modifying said pseudorandom number of the second sequence with said last mentioned signal to provide a congruent access code signal and in response to the equality of the congruent access code signal and transmitted access code signal providing an access signal, and means receiving the access signal and in response thereto establishing a data transmission path between the terminal and the computer, said first and second sequences being the same, whereby computer access is secured through a sequential change of access codes in a pseudorandom fashion without direct transmission of said user'"'"'s password.
-
9. A method of accessing a computer at one location by a user positioned at a second location and having an assigned password, the method comprising the steps of
(a) sequentially generating a nonrecurring pseudorandom number of a first sequence at the second location, (b) modifying the pseudorandom number as a function of the user assigned password to provide an access code, (c) transmitting the access code and an identifying signal unique to the second location from the second location to the first location, (d) receiving the transmitted access code and identifying signal at the first location, (e) in response to the identifying signal, sequentially generating a pseudorandom number of a second sequence congruent with said first sequence, at the first location, and also generating, in response to the identifying signal, a signal corresponding to the user assigned password, (f) modifying the pseudornandom number of the second sequence with said last mentioned signal corresponding to the user assigned password to provide a congruent access code, (g) comparing the received access code with the congruent access code, and (h) granting access to the computer upon recognition of an equality between the received access code and the congruent access code, whereby computer access is secured through a change of access codes in a pseudorandom fashion without direct transmission of the user'"'"'s password.
-
14. A system for accessing a computer by a user having an assigned password to establish a communication link for data transmission between a computer terminal and a computer via a data transmission path, said system comprising a portable access unit connected as a peripheral to said terminal and comprising:
-
(a) means sequentially generating nonrecurring pseudorandom numbers in a reproducible fashion, and (b) means modifying said pseudorandom numbers as a predetermined function of said password to provide a first access code, and means applying said access code and a unique identifying signal to said data transmission path prior to data from said computer terminal;
said system further comprising, at said computer;(c) means for sequentially generating pseudorandom numbers congruent with those generated by said access unit in response to the reception of said identifying signal, (d) means responsive to said identifying signal for generating a signal corresponding to said user assigned password and for modifying said congruent pseudorandom numbers with said last mentioned signal to provide a second access code, (e) means for receiving said first access code and comparing it with said second access code and in response to the equality thereof providing an access signal, (f) means receiving the access signal and in response thereto establishing a data transmission path between the terminal and the computer, whereby computer access is secured through a sequential change of access codes in a pseudorandom fashion without direct transmission of the user'"'"'s password. - View Dependent Claims (15, 16, 17, 18)
-
- 19. In a system comprising a computer coupled to a plurality of terminals, the improvement comprising a plurality of portable access units each adapted to be inserted at one of said terminals between the respective terminal and said computer, each said access unit comprising a pseudorandom number generator for sequentially generating a separate pseudorandom sequence, a source of an identifying signal unique to the respective unit, means for receiving a password from a user, means modifying the pseudorandom numbers of the respective sequence by said passwords, means transmitting to the computer the identifying signal and the access code, and means passing data between the terminal and computer, said system further comprising a controller at said computer, said controller comprising means for receiving the identifying signals from the access unit, and, in response thereto, sequentially generating a pseudorandom number congruent with the sequence of the given access unit and also generating a signal corresponding to the password of the respective access unit, to provide an access code signal generated therein, means for modifying the pseudorandom number generated in said controller by said access code signal generated therein to produce a congruent access code, and means responsive to equality of the congruent access code and first mentioned access code for enabling access of the respective terminal to said computer.
Specification