The Low Cost Threshold Implementation Method of uBlock Algorithm Against Side Channel Attacks

In traditional cryptographic analysis based on black box model,atackers can only use the input and outputinformation of cryptographic algorithm to attack, and the security of existing cryptographic algorithms under black box model has been fully demonstrated. However, under the grey box model, the ability of the attacker is improved.It can notonly obtain the input and output information of the cryptographic algorithm, but also obtain the power consumption, electromagnetic, optical and other physical information leaked during the actual implementation of the cryptographic algorithm. The correlation between the physical information and the intermediate state of the cryptographic algorithm can be used by the adversary to recover the secret information, which is called the side-channel attack. Since the side-channel attack was proposed, it has posed a serious threat to the security of the implementation security of cryptography algorithm because of its relatively low implementation cost and high attack efficiency. uBlock algorithm is the first prize winning algorithm of block cipher in 2019 National Cryptographic Algorithm Design Competition, which is also threatened by side channel attacks. Now study of uBlock algorithm is less, in terms of hardware implementation mainly consider low delay implementation and high throughput, and lack of low-cost optimization implementations for resource-constrained situations, and it is not conducive to the construction of protection scheme against side-channel attack. The current public literature points out its S-box is suitable for the construction of side channel protection scheme based on threshold implementation, and there is a 3-sharc threshold implementation scheme without new random number during the execution of the algorithm, but docs not give a concrete implementation scheme. In view of this situation, this paper firstly designs and implements a low cost hardware implementation scheme suitable for uBlock algorithm based on pipeline and serialization. Secondly, based on the above low cost implementation scheme, a 3-share threshold implementation scheme without new random numbers is constructed and implemented for uBlock algorithm. Finally, aiming at the problem that the implementation area of 3-sharc threshold protection scheme consumes a large amount, the implementation cost is further optimized, and a 2-share threshold protection scheme without new random numbers is constructed and implemented. In order to verify the actual security of the above protection schemes, this paper carried out the actual implementation in FPGA development board, and carried out the side-channel evaluation experiments based on the test vector leakage evaluation technology. Experimental results verify that 3-sharc and 2-sharc threshold protection schemes of uBlock algorithm have the corresponding protection ability against side channel attacks. In order to further compare the realization cost of protection schemes, this paper compares each scheme from the perspective of register consumption, random number consumption and delay, and then evaluates the consumption of different schemes in FPGA resources, equivalent gates through experiments. All in all, the cost comparison above shows that the resource consumption of 2-share threshold implementation without new random number is the lowest compared with other protection schemes, and the area consumption of 2-sharc threshold implementation without new random number is reduced by about 30% compared with 3-share threshold implementation without new random number. © 2023 Science Press. All rights reserved.