Side channel power analysis of an AES-256 bootloader

Abstract— Side Channel Attacks (SCA) using power measurements are a known method of breaking cryptographic algorithms such as AES. Published research into attacks on AES frequently target only AES-128, and often target only the core Electronic Code-Book (ECB) algorithm, without discussing surrounding issues such as triggering, along with breaking the initialization vector. This paper demonstrates a complete attack on a secure bootloader, where the firmware files have been encrypted with AES-256-CBC. A classic Correlation Power Analysis (CPA) attack is performed on AES-256 to recover the complete 32byte key, and a CPA attack is also used to attempt recovery of the initialization vector (IV).

• Type: Journal
• Year: 2015
• Where: CCECE
• Authors: Colin O'Flynn, Zhizhang (David) Chen
• Keywords: CCECE 2015, Electrical And Computer Engineering