Title:
【発明の名称】秘話移動電話
Document Type and Number:
Japanese Patent JPS59501288
Kind Code:
A
Abstract:
An arrangement for generating an encryption key for use in encrypting communications between a mobile radio telephone unit and a base station is disclosed which can be readily changeable in real time. Each mobile unit is equipped with a machine-readable nonbroadcast code and the base station can access a translation table correlating the nonbroadcast code with the public directory number of the mobile unit. Upon changing frequencies, as for example, when a mobile unit moves from one geographical cell area to another, the current and previous frequencies or channel numbers are left to select sets of digit positions in the nonbroadcast code. The contents of these digit positions are then convolved and inserted into a modified version of the nonbroadcast code generated by convolving the original code with a shifted replica thereof. The key so generated may be used to encrypt communications for the use of any known encrypting circuitry.
Inventors:
Ropinto-Frank Jiyoung
Application Number:
JP50069383A
Publication Date:
July 19, 1984
Filing Date:
January 24, 1983
Export Citation:
Assignee:
Western Electric Campani, Inco-Polesed
International Classes:
H04K1/02; H04B7/26; H04L9/06; H04L9/08; H04L9/14; H04L9/22; H04W12/04; (IPC1-7): H04B7/26; H04K1/02; H04L9/02
Attorney, Agent or Firm:
Masao Okabe