On reusing ephemeral keys in Diffie-Hellman key agreement protocols. (31st January 2011)

• Record Type: Journal Article
• Authors: Menezes, Alfred; Ustaoglu, Berkant
• Is Part Of: International journal of applied cryptography. Volume 2:Number 2(2010)
• Page Start: 154
• Page End: 158
• Publication Date: 2011-01-31
• Subjects: key agreement protocols -- Diffie-Hellman -- ephemeral public keys -- cryptography -- computational workload -- denial-of-service attacks -- ephemeral key reuse -- domain parameter selection -- public key validation; Data encryption (Computer science) -- Periodicals; Cryptography -- Periodicals; Computer security -- Periodicals; 652.8
• Languages: English
• ISSNs: 1753-0563

Abstract

A party may choose to reuse ephemeral public keys in a Diffie-Hellman key agreement protocol in order to reduce its computational workload or to mitigate against denial-of-service attacks. In this note, we show that small-subgroup attacks can be successfully launched on some Diffie-Hellman protocols that reuse ephemeral keys if domain parameters are not appropriately selected or if public keys are not appropriately validated.