To mitigate the risks of device impersonation and information eavesdropping faced by urban rail transit safety equipment in open network environments, this paper proposes a system scheme for lightweight Public Key Infrastructure (PKI) based on domestic cryptographic algorithm (SM algorithm), which takes into account the certificate issuance scheme for administrative management needs. First, based on the characteristics of urban rail transit, a hierarchical X.509 certificate system signed with the SM2 algorithm was designed. Then, leveraging the public key information embedded in the certificates, a three-way handshake protocol was proposed to achieve session key negotiation in a fully open network environment. Finally, communication procedures for intra-domain and inter-domain device handshakes were constructed, and their performance (efficiency) was analyzed. The results show that the proposed system still ensures point-to-point encrypted communication between devices even if all inter-device communication data are fully exposed. The device-to-device key negotiation takes approximately 214.5 ms under average conditions and about 2557.5 ms in the worst case; both values are far below the duration of the communication overlap zone when a train transitions between regional control centers, thereby ensuring acceptable efficiency.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |