A dynamic quantum-resistant code-based public key encryption scheme

Code-based post-quantum cryptography is seeing an unprecedented growth due to its significance in addressing the security threats posed by quantum computers toward digital communication, leveraging its strength from the well-known hard problems of coding theory. Code-based cryptosystems are vulnerable to attacks that exploit the inherent structure of the underlying code, compromising security in many cases. Although McEliece cryptosystem with Goppa codes provide substantial resistance, this comes at the cost of huge key sizes, limiting their practicality. The proposed work, dynamic code-based McEliece cryptosystem, introduces the notion of dynamicity to the code-based cryptosystem and intensifies the random nature necessary to overcome the attacks. Unlike the conventional schemes that rely on a fixed underlying code and its generator matrix, our approach dynamically changes the code structure in response to trigger events to create cipher keys. This dynamic code transformation preserves the core efficiency of the cipher while significantly improving security against structural attacks, decoding attacks and side channel analysis. The proposed scheme retains IND-CPA security under standard assumptions while also rendering chosen ciphertext attacks significantly challenging. Our work establishes a new direction for enhancing the security of code-based encryption in practical applications.