Worked on the google-auth-library-java repository to enhance authentication reliability by addressing a bug in client-side CAB token generation. Focused on backend development and API security using Java, the work involved removing Base64 padding from CAB tokens to ensure consistency with server-side behavior and to prevent URL-encoding compatibility issues. Expanded unit test coverage to verify the absence of padding across all CAB token paths, providing protection against future regressions. This approach improved the robustness of authentication flows and reduced the risk of production incidents related to encoding errors, demonstrating a methodical, test-driven approach to maintaining secure and compatible backend systems.