Card verification system using stored functions Patent #: 4219151
ApplicationNo. 773315 filed on 10/10/1991
US Classes:380/247, CELLULAR TELEPHONE CRYPTOGRAPHIC AUTHENTICATION340/5.42, Debiting (e.g., rental)340/5.74, Access to electrical information380/43, Key sequence signal combined with data signal380/257, Circuit switched network (e.g., wired telephone)455/405, Usage measurement455/410, Security or fraud prevention455/558, Card control element705/400FOR COST/PRICE
ExaminersPrimary: Gregory, Bernarr E.
Attorney, Agent or Firm
Foreign Patent References
International ClassH04L 009/32
Foreign Application Priority Data1990-10-10 FR
AbstractIn the course of the intercommunication between the base station and the autonomous telephone set, the first means of authentication initially generates a keyword dependent on the call charge for the current service and transmits it to the autonomous telephone set. The second means of authentication then calculates the transform of the keyword by the encryption function F with the aid of the subscriber's secret key, and transmits the transform to the first means of authentication which finally checks the authenticity of the transform to totally block the intercommunication if the authenticity is not confirmed by the check.