Serialization and Transmission of CKKS Ciphertexts over Inter Integrated Circuit (I2C) Bus

Data in use is primarily stored in volatile memory, such as random access memory (RAM), memory caches, and registers when they have been decrypted for processing. These data are vulnerable to exploitation or encryption keys being stolen from the devices. In most traditional architectures, the central processing unit (CPU) and main memory work together because they share a common communication bus, so the same data moves within their circuits. The internal bus channel connects all the internal components of a computer, such as the registers, CPU and memory, to the motherboard. Although encryption can protect data during transmission, most conventional cryptographic schemes will required that the ciphertext is decrypted before processing of data. Fully homomorphic encryption (FHE) provides an alternative by allowing computation on encrypted data. This study investigates the process of serializing and transmitting FHE ciphertexts through I2C channels on resource constrained microcontrollers. Keywords: Fully Homomorphic Encryption, OpenFHE, CKKS, AES, I2C, STM32F411CEU6, Embedded systems, IoT Security.