Cryptology ePrint Archive: Report 2006/052

Software mitigations to hedge AES against cache-based software side channel vulnerabilities

Ernie Brickell and Gary Graunke and Michael Neve and Jean-Pierre Seifert

Abstract: Hardware side channel vulnerabilities have been studied for many years in embedded silicon-security arena including SmartCards, SetTop-boxes, etc. However, because various recent security activities have goals of improving the software isolation properties of PC platforms, software side channels have become a subject of interest. Recent publications discussed cache-based software side channel vulnerabilities of AES and RSA. Thus, following the classical approach --- a new side channel vulnerability opens a new mitigation research path --- this paper starts to investigate efficient mitigations to protect AES-software against side channel vulnerabilities. First, we will present several mitigation strategies to harden existing AES software against cache-based software side channel attacks and analyze their theoretical protection. Then, we will present a %thorough performance and security evaluation of our mitigation strategies. For ease of evaluation we measured the performance of our code against the performance of the openSSL AES implementation. In addition, we also analyzed our code under various existing attacks. Depending on the level of the required side channel protection, the measured performance loss of our mitigations strategies versus openSSL (respectively best assembler) varies between factors of 1.35 (2.66) and 2.85 (5.83).

Category / Keywords: implementation / AES, Countermeasures, Computer architecture, Computer security, Software side channels

Date: received 13 Feb 2006

Contact author: jean-pierre seifert at intel com

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Version: 20060214:163143 (All versions of this report)

Discussion forum: Show discussion | Start new discussion


[ Cryptology ePrint archive ]