Session protocol for backward security between paired devices

US10271209B2 · kind B2 · utility

Assignee

• Apple Inc. · US

Inventors

• Mitchell D. Adler · Cupertino, US
• Yannick L. Sierra · San Francisco, US
• Ganesha A. G. Batta · Cupertino, US
• Michael J. Giles · San Jose, US
• Akshay Mangalam Srivatsa · Santa Clara, US
• Craig P. Dooley · Los Gatos, US
• Sriram Hariharan · San Jose, US
• Robert D. Watson · Tijeras, US

Key dates

• Filing date: Sep 23, 2016
• Grant date: Apr 23, 2019
• Expiry date: Feb 23, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04W84/18
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

Some embodiments provide a method for establishing a secured session with backward security between a first device and a second device. In some embodiments, the method establishes a communication session between the first and second devices using shared keys stored at the first and second devices. The method exchanges encrypted data between the first and second devices as a part of the communication session. The method, upon completion of the communication session, modifies the shared key at the first device in a predictable way. The shared key is modified at the second device in the same predictable way. The method then stores the modified shared key at the first device. The modified shared key cannot be used to decrypt any portion of the encrypted data of the current and previous communication sessions.