CRM_BF:A Low-Overhead, High-Efficient and Reconfigurable Operation Unit Design Approach Using the Customized Reed-Muller Unit For Boolean Functions of Sequence Cipher Algorithms

Sequence ciphers algorithms encrypt or decrypt information at a low cost and high speed compared to other cryptographic algorithms, which are widely applied to critical applications and sensitive fields. As the core component of sequence ciphers, Boolean functions generate the random number or implement the update process of random numbers. The existing implementations of Boolean functions cause a great waste of area resources and generate several long critical paths that limit the hardware performance of sequence ciphers. To address this issue, a 64-bit Boolean Function Reconfigurable Operation Unit (BFROU) is proposed to reduce the area overhead, lower the delay latency, and enhance the operation efficacy of Boolean functions. Through statistical characterization analysis and cutting experiments of Boolean functions, a 64 bits BFROU based on CRM-3 units has been designed, which has the advantage of low-cost and high-efficient。The CRM unit is customized based on RM logic. A theoretical framework for Boolean functions is proposed by combining CRM units with mathematical expressions, which encompasses Boolean functions for any variable. On the platform of synthesis software, based the theoretical architecture, a CRM-OPT optimization algorithm is proposed, which can achieve the conversion of And Inverter Graph (AIG) to Customized Reed Muller Graph (CRMG).This Customized Reed-Muller (CRM) unit achieved at least 22.4% and 25.1% optimization in delay and area compared to Universal Reed-Muller (URM) units. The experimental results show that the Area Delay Product (ADP) is minimized when the CRM-3 unit is the optimal maximum cutting size. Ultimately, the BFROU design was realized utilizing CRM units, achieving an area of 195.4um² and a critical path delay of 0.35ns. This BFROU can achieve special Boolean functions involving 64 variables at maximum,with 91% of these functions being mapped within two iterations. Moreover, this BFROU has significant advantages over other known schemes regarding area, critical path delay, ADP, and number of iterations consumed.