Design And Research Of A Broadcast Encryption Scheme Based On The National Cryptographic Algorithm SM2

The broadcast encryption mechanism is a one-to-many encryption method in which the broadcaster securely distributes information to a collection of receivers through a public channel.Only users inside the collection can decrypt the broadcast information,while those outside the collection cannot obtain it.Compared with the traditional one-to-one public key encryption mechanism,broadcast encryption has a wider range of applications,such as pay TV,satellite broadcast communication,and digital rights distribution(CD/DVD).To achieve independent control of cryptographic technology,the State Cryptography Administration released the SM2 algorithm in 2010.This domestic commercial cryptographic algorithm is based on elliptic curve design and offers short key length,small system parameters,and high security compared with RSA and other public key cryptographic schemes.However,SM2,being a one-to-one encryption mechanism,encounters challenges in terms of computational costs and communication overhead,thereby limiting its applicability in scenarios involving secure data sharing among multiple recipients.This paper proposes a secure and efficient broadcast encryption scheme based on the Chinese national cryptographic algorithm SM2 for public key encryption,integrated with polynomial secret sharing,with the objective of expanding the applicability of SM2 in a multi-recipient environment.The proposed scheme provides its IND-CCA security under the Oracle Diffie-Hellman assumption.The scheme also offers low computational and communication overheads,fixed system parameters and public and private key sizes,and linear correlation between ciphertext length and the number of receivers.Additionally,the scheme is dynamic and anonymous,allowing the system to add and reduce users as needed,and receivers cannot obtain information about other receivers in the set when decrypting.Finally,the paper shows that the proposed broadcast encryption scheme outperforms SM2 encryption by about 50% for the same number of receivers.The decryption overhead of the proposed scheme is also more stable and less affected by the number of receivers.Therefore,the proposed scheme not only has the performance of the SM2 public key encryption algorithm but also has wider application scenarios.