An efficient and secure distributed scheme for SM2 decryption in Internet of Things

Elliptic Curve Cryptography(ECC) is widespread in practical applications because compared to other asymmetric cryptosystems, ECC can achieve the same level of security with shorter key lengths. With the development of the Internet of Things(IoT), a great deal of constrained devices may require software ECC implementations. However, point multiplication, which is the most time-consuming operation, restricts the use of ECC in these devices. In order to improve the efficiency of the SM2 algorithm based on ECC in IoT, we propose an efficient and secure distributed scheme for SM2 decryption. In this proposed scheme, the SM2 private key is covertly divided into key shares of different lengths, which are then distributed to various devices to ensure the privacy of the key. Additionally, high-performance devices handle auxiliary point multiplication calculations, improving the decryption speed and alleviating the burden of local calculations. Performance analysis and experiments demonstrate that the scheme achieves nearly 3.8 times faster decryption than the standard SM2 algorithm, making it suitable for IoT applications.