Cryptology ePrint Archive: Report 2020/684

Legally keeping secrets from mobile operators: Lawful Interception Key Exchange (LIKE)

Ghada Arfaoui and Olivier Blazy and Xavier Bultel and Pierre-Alain Fouque and Adina Nedelcu and Cristina Onete

Abstract: How to balance user privacy with a law enforcement agency's need to view their communications during investigations has always been a delicate and hard to formalize problem. In the age of analog communication, interception was as simple as "wiretapping" a telephone line. Due to technological advances, this is now mandated, at least in the context of mobile communications, by laws and standards pertaining to lawful interception. We introduce a new primitive, called Lawful Interception Key-Exchange (or LIKE), that guarantees key-security (up to a collision of n-1) authorities, as well as a series of novel properties, such as non-frameability and honest operator. Our approach is generic enough to be adapted to a number of use cases, is more privacy preserving than existing implementations and strikes the right balance between security and exceptional access.

Category / Keywords: cryptographic protocols / Authenticated Key Exchange, key escrow, lawful interception

Date: received 8 Jun 2020

Contact author: adina nedelcu at orange com,cristina onete@gmail com

Available format(s): PDF | BibTeX Citation

Version: 20200609:233812 (All versions of this report)

Short URL: ia.cr/2020/684


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