ChaCha20-AES Combined Algorithm with 512 Bits of Security

IBM introduced the Condor quantum computer of 1121 Qbit in December 2023, which provides practical advances in quantum computing. Grover's quantum search algorithm reduces the security of current encryption algorithms to proportionate to half of the key size. Consequently, quantum-resilient algorithms become a vital necessity. Moreover, current processor platforms support a hardware implementation of advanced encryption standard (AES) accelerators. Redesigning the AES structure to gain higher security levels leads to the loss of utilizing hardware accelerators. This paper introduces an AES-based 512-bit encryption algorithm that keeps the internal structure for the AES utilizing the hardware AES accelerator. The proposed encryption algorithm is designed to be a combination of ChaCha20 and AES which are two secure and powerful cryptographic algorithms. ChaCha20 with Little tweak is used for the key scheduling algorithm and pseudo-random generator for secure IVs. The proposed algorithm provides 256 bits of security against quantum adversaries.