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Title: Power analysis attacks and countermeasures for block ciphers
Author: Boey, Kean Hong
ISNI:       0000 0004 2740 8508
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2012
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In today's digital world, cryptographic algorithms are commonly used in all aspects of our daily life. Whilst most of the modem cryptographic algorithms are secure against theoretical attacks, cryptographic algorithms can be compromised by monitoring the power consumption, which is known as power analysis attacks. The differential power analysis (DPA) attack is the most powerful attack. Although several countermeasures have been proposed to defend against power analysis attacks, these countermeasure techniques are costly to develop or need to be designed for specific encryption algorithms. In this thesis, a number of techniques and practical experiments have been undertaken to explore DPA attacks in more detail. DPA attacks were performed on two block cipher encryption algorithms CAST-128 and SEED. These two block ciphers use two round keys in each round function. However, existing power analysis attack strategies are not suitable for cryptographic algorithms that use two round keys in each round function. Therefore, two attack strategies have been proposed and targeted at the SBox component, in each of the algorithms to reveal the round keys. Unlike previous research which has mostly focused on simulation-based analysis of the SBox component, this research involved a focused analysis of DPA attacks of hardware implementations of the SBox component to investigate which SBox are more secure against such attacks. Based on this analysis, some recommendations for more power resistant SBox functionality were proposed. In this research two novel countermeasures, which misalign the power traces by randomly inserting idle cycle(s) or dummy cycle(s) in between two or more consecutive operations, are proposed to counteract power analysis attacks. The proposed countermeasures can be used to increase the resistance of a cryptographic device by reducing the overall SNR by more than 94%. Both the proposed countermeasures are better in terms of area and power consumption than other countermeasure techniques.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available