This Safety, Security, and Privacy of Open-Source Ecosystems (Safe-OSE) project focuses on improving a critical piece of open-source software utilized by U.S. government agencies for national security and foreign policy purposes, by U.S.-based companies and organizations to deliver their services, and by individual citizens of the U.S. to bolster their privacy online. The project will focus on transitioning the software to a stronger form of encryption, ensuring that all users of the software are protected against evolving threats posed by quantum computing. The project will also resolve vulnerabilities posed by a variety of other threats that can compromise the safety, security, or privacy of the software’s users, including threats from outside governments, potential malicious developers who might try to inject compromised code into the software’s dependencies, and insiders that have had their accounts compromised through phishing attacks, and more. This Safe-OSE project addresses the software’s (1) potential weakness to decryption caused by its use of pre-quantum encryption algorithms and (2) potential weaknesses to socio-technical threats like supply-chain attacks, long- and short-term infiltration, foreign government compromise, and compromised infrastructure. The project will (a) convert existing threat model findings into concrete security implementation measures; (b) implement supply chain resilience for automated dependency management; (c) provide a reproducible im