# Low-Cost Full Correlated-Power-Noise Generator to Counteract Side-Channel Attacks
###### Abstract  
Considerable attention has been given to addressing side-channel attacks to improve the security of cryptographic hardware implementations. These attacks encourage the exploration of various countermeasures across different levels of abstraction, through masking and hiding techniques, mainly. In this paper, we introduce a novel hiding countermeasure designed to mitigate Correlation Power Analysis (CPA) attacks without significant overhead. The new countermeasure interferes with the processed data, minimizing the power correlation with the secret key. The proposed method involves using a Correlated-Power-Noise Generator (CPNG). This study is supported by experimental results using CPA attacks on a SAKURA-G board with a SPARTAN-6 Xilinx FPGA. An Advanced Encryption Standard (AES) cipher with 128/256-bit key size is employed for this purpose. The proposed secure design of AES has an area overhead of 29.04% compared to unprotected AES. After conducting a CPA attack, the acquisition of information about the private key has been reduced drastically by 44.5%. CPA attacks; hiding countermeasures; correlated power noise generator; FPGA; AES; hardware security +
Footnote †: journal: Applied sciences  
0000-0001-5000-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-00000-00000-0000-00000-00000-00000-00000-00000-00000-00000-  
information during encryption. This area of exploration, known as Side-Channel Analysis (SCA), has remained dynamic over the past two decades [1]. During a SCA attack on the cryptographic device, the secret key is exposed while the device operates correctly during encryption. Namely, although conventional cryptographic algorithms, for instance, even the ciphers Advanced Encryption Standard (AES) or ASCON, are designed to obfuscate sensitive data and safeguard them against unauthorized access, they remain susceptible to physical attacks. Power analysis (PA) is one of the most common SCA attacks and has attracted significant attention because of its effectiveness and because it can be carried out relatively easily [1], meaning a substantial security threat to cryptographic devices. Indeed, unprotected cryptocircuits can be broken with slight effort. The main idea of PA attacks is to use the relationship between the power consumed by the device and the data being computed to find secret data such as the key to an encryption process. Some PA techniques are Differential Power Analysis (DPA) and Correlation Power Analysis (CPA) [3]. This kind of attack exploits target circuit power with a hypothetical model. Those predictions are subsequently compared to the real power traces to recover the private data [3]. To mitigate such attacks, countermeasures can be employed to enhance the security of cryptographic devices. These countermeasures can be categorized at three distinct levels: gate, system, and algorithmic. On the other hand, depending on the technique used to break the data correlation with the power consumption, we can classify the countermeasure into two main groups: the hiding or masking technique. The hiding technique attempts to have the same power consumption or a random power consumption independently of the data being processed. In order to obtain the same power consumption, one of the most widely used strategies is the use of dual-rail logics such as SABL or WDDL [4; 5]. On the other hand, we find countermeasures that generate power consumption contributions understood as dummy by means of noise generators, hiding the real consumption of our cryptographic circuit. In masking, the critical data are masked with a random data sequence during encryption such that operations on the masked data are indistinguishable from random data [1; 6]. In embedded design scenarios, all these countermeasures are resource-intensive. In light of the imperative requirement to minimize both the area overhead and power consumption in specific embedded devices, novel and cost-effective architectural countermeasures are demanded.