04310720 is referenced by 179 patents and cites 20 patents.

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.

Title
Computer accessing system
Application Number
6/892252
Publication Number
4310720
Application Date
March 31, 1978
Publication Date
January 12, 1982
Inventor
Frank T Check Jr
Orange
CT, US
Agent
Albert W Scribner
William D Soltow Jr
David E Pitchenik
Assignee
Pitney Bowes
CT, US
IPC
H04L 9/00
View Original Source