Current cloud environments commonly use perimeter-based security mechanisms， only relying on firewall port policies or simple authentication for access control， so there are several limitations： first， they may lead to identity theft and repudiation among internal entities， lateral movement， traffic-based attacks， or sensitive data leakage； second， the existing mechanisms such as JWT （JSON Web Token） and TLS （Transport Layer Security）， though partially adopted， still suffer from replay attacks， port exposure， and management complexity. To address these risks， we proposed a Non-Person Entity （NPE） identity registration and authentication scheme based on the zero-trust principle. In the scheme， we designed a multi-level identity registration mechanism and employed the Chinese national cryptographic algorithm SM9 to achieve NPE key generation， identity binding， and automatic distribution. By improving the existing Single Packet Authorization （SPA） technique and integrating JWT， we realized bidirectional authentication and fine-grained authorization among NPEs. Security analysis shows that the proposed scheme can mitigate Distributed Denial-of-Service （DDoS） attacks and resist various network threats such as replay and man-in-the-middle attacks， offering security advantages over authentication schemes such as JWT， TLS and UDP （User Datagram Protocol）-based SPA. Experimental results demonstrate that compared with the Software-Defined Perimeter （SDP） controller-based authentication scheme， the proposed scheme reduces the communication latency by 50% and decreases the authentication overhead by 62.03%.