The Senior Software Security Engineer will enhance product security at Cash App by threat-modeling features, designing security mechanisms, and collaborating with product teams. Key responsibilities include driving security projects, educating fellow engineers, and building abstractions for security. The role demands hands-on leadership in delivering security solutions across the organization's technology stack.

The Senior Security Engineer will co-design and co-build security features for Cash App's Bitcoin platform, ensuring secure handling of Bitcoin holdings. Responsibilities include developing security mechanisms, maintaining the open-source cold storage system, and contributing to the security infrastructure across the platform.