Attacking an Obfuscated Cipher by Injecting Faults

Date Added: Jan 2011
Format: PDF

The authors study the strength of certain obfuscation techniques used to protect software from reverse engineering and tampering. They show that some common obfuscation methods can be defeated using a fault injection attack, namely an attack where during program execution an attacker injects errors into the program environment. By observing how the program fails under certain errors the attacker can deduce the obfuscated information in the program code without having to unravel the obfuscation mechanism. They apply this technique to extract a secret key from a block cipher obfuscated using a commercial obfuscation tool and draw conclusions on preventing this weakness.