Methods and apparatus for self-inverting multiple-iteration CMEA crypto-processing for improved security for wireless telephone messages

US6418224B1 · kind B1 · utility

Assignee

• LUCENT TECHNOLOGIES INC. · US

Inventors

• Mark H. Etzel · Harvard, US
• Robert John Frank · Silver Spring, US
• Daniel Nelson Heer · Berlin, DE
• Robert Joseph McNelis · Columbia, US
• Semyon B. Mizikovsky · Morganville, US
• Robert J. Rance · Bradford, US
• R. Dale Shipp · Columbia, US

Key dates

• Filing date: May 5, 1998
• Grant date: Jul 9, 2002
• Expiry date: May 5, 2018

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2209/80
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A self-inverting enhanced CMEA encryption system suitable for use in wireless telephony. An unprocessed text message is introduced into the system and subjected to a first iteration of a CMEA process, using a first CMEA key to produce a first intermediate message, a first intermediate processed text message, a first intermediate ciphertext message or the like. The first intermediate processed text message is subjected to a further iteration of the CMEA process, using a second CMEA key, to produce a second intermediate processed text message. The second intermediate processed text message is subjected to a final iteration of the CMEA process, using the first CMEA key, to produce the final processed text message. Security may be additionally enhanced by subjecting each message to an input/output transformation before and after each iteration of the CMEA process. In a three-iteration process, a total of four input/output transformations are used with the first and fourth input/output transformations being identical, and with the second and third input/output transformations being identical.