Research On Side Channel Attack Countermeasures Of Encryption Chip

Power analysis method is a side channel attack method which got widelyattention and application, it observes the power variation characteristic whenencryption chip running, research the correlation of processing data and powerconsuming, to reason the Key stored in the chip according to correlation. For ourapproach is easy and the attack ability is strong, this approach is widely adopted.It can attack the chip with all kinds of encryption algorithm, not constrained by aspecific algorithm. Differential power analysis (DPA) and high order DPA (H-ODPA) attack ability is stronger, with the development of research, theimplementation approach is mature, the cost reduced dramatically, they seriouslythreaten encryption chip. There are many improved power attack approach aim atthe specifically encryption algorithm and the attack effect is better.Our thesis aimed at the characteristic of power attack technology and criticaltechnology, especially DPA and high order DPA, to proposes improved specifydefend approach, to enhance encryption chip defeat DPA, to design the encryptionchip and simulation. To research the defend approach according to new attackapproach, our main works are as follows:1) Propose defend method which modified AES algorithm. Introduce therandom method and Transformed Masking Method (TMM) to modify AESalgorithm, to implement with the inverse operation of GF(2~8) in the AESalgorithm with the Simple Dynamic Differential Logic (SDDL) logic. Theanalysis indicates that success attack need (16+4~*n)~2 times trace than thestandard DPA, this is infeasible. The simulation experiment indicates that ourapproach can defend the zero value attack.2) Propose an improved method with masking approach DES encryption chip,to modify the S box instead of restoring the key before proceeding data inputs-box, it can protect key and to eliminate data masking after the transformation ofS box. There exist XOR masking and Addition masking operation in the DESalgorithm, we implement the approach to transform in the XOR masking and Addition masking operation, the sensitive data will not appear in the cipher textand is completely masked. The simulation result indicates it can defend thecorrelation attack, superposition attack and so on3) Propose improved Unique Masking Method (UMM) algorithm whichcombines algorithm level and logic level method aiming at DES encryptionsystem; Research the characteristic of Sense Amplifier Based Logic (SABL),design power consuming balance SABL cell library, semi-custom design flow andpoint out the reason to implement S box with SABL. The security analysis andsimulation experiment shows our approach can defend the high-order DPA attack.4) Design the DES chip which can defend high order DPA attack. To modifythe S box, add one random number and two groups of S boxes. To achieve theDES chip critical module with SABL, non-critical module is implemented withCMOS, then construct the whole DES chip finally. To tradeoff some performanceindex in the implementation process consider the restriction of smartcard, a partsegment pipeline was used in its structure. To implement simulation analysis withthe performance and comparison with the chip in existence, it shows that the chipcan achieve encryption and decryption. The new approach improved the ability ofdefending high order DPA attack, reduced the resource consuming in the meantime.