A Multi-Authority RSA Broadcast Encryption Scheme Based on Modulus Ni

With the development of network technology, multicast and broadcast communications have gradually replaced unicast communication. Traditional RSA encryption is no longer suitable for many network applications, such as scenarios where multiple users with different privilege levels access paid content. This paper demonstrates the limitations of the key management protocol proposed by Lin in 2004 under a multi-privilege user system and redefines the algorithm for generating the modulus N_i, achieving a hierarchical division of privilege levels. Based on this key management protocol, a new multi-privilege RSA broadcast encryption scheme is proposed, addressing the limitations of traditional RSA encryption in one-to-many communication scenarios and taking into account the different privilege levels of users. This scheme allows high-privilege users to decrypt more information, while low-privilege users decrypt less information, adapting to the needs of practical applications. By dynamically dividing user privilege levels and distributing private keys of different decryption levels accordingly, the system enables dynamic user addition and removal, enhancing the scalability and flexibility of the system. This expands the application scenarios of RSA encryption while increasing its security and practicality.