Sheng Jiang developed ECDSA-P384 support for JWT signing and verification in the google-auth-library-python repository, introducing new EsSigner and EsVerifier classes to handle both ECDSA-P256 and ECDSA-P384 keys. He focused on Python cryptography and modular API design, ensuring backward compatibility while aligning with Google Distributed Cloud requirements. Sheng validated the implementation through end-to-end testing against GDC instances, confirming robust handling of both key types without regressions. His work enabled compliant key onboarding for GDC customers and strengthened the library’s security posture. The project demonstrated depth in API development, JWT handling, and careful refactoring to support evolving cryptographic standards.