Worked on security hardening within the openssl/openssl repository, focusing on the SM2 encryption path using C and cryptography expertise. Addressed memory-safety concerns by implementing ciphertext size validation, ensuring that outputs never exceed the caller-provided buffer and preventing buffer overflows. Enhanced the reliability of the OpenSSL API for users relying on SM2 encryption by adding pre-write checks and rejecting unsafe outputs. Further improved cryptographic test reliability by fixing buffer length reinitialization in EVP_SM2 encryption and decryption tests, reducing the risk of flaky CI and production issues. Demonstrated careful unit testing and collaborative code review throughout the development process.