Senior Security Software Engineer - iCloud Security Infrastructure

This isn't security work on the margins. You'll be working deep in the stack - interfacing directly with low-level Linux kernel primitives, designing security architecture that operates at global scale, and making critical technical decisions that shape how iCloud protects its users worldwide. You'll be part of a highly skilled team within Apple Services Engineering that provides foundational security infrastructure underpinning consumer-facing iCloud applications and services. The performance and correctness of the systems we build are paramount. We work directly with low-level Linux kernel interfaces, leveraging asynchronous I/O and multithreaded architecture to build high-throughput, low-latency secure services. In this role, you will not only execute on technical deliverables but serve as a key contributor to the architectural and strategic decisions that define the team's direction. Minimum Qualifications BS in Computer Science and/or equivalent experience 10+ years of industry experience in systems software engineering Deep proficiency in C and/or C++ - writing systems-level code, not just calling libraries Strong networking fundamentals including TCP/IP, TLS, and protocol design Demonstrated expertise with Unix/Linux internals and operating system concepts Solid understanding of software security primitives including cryptography, authentication protocols, and secure coding practices Familiarity with distributed systems design principles and token-based architecture Strong written and verbal communication skills with the ability to convey complex security concepts to diverse audiences Preferred Qualifications Hands-on experience designing or implementing token-based authentication systems such as OAuth, JWT, macaroons, or proprietary token frameworks Experience with modern security technologies including HSMs, PKI, secrets management, or secure enclaves Familiarity with additional systems languages including Go, Rust, Swift, or Java Background in cloud services security, identity and access management (IAM), or internet-scale security infrastructure Experience building and operating security systems at large-scale production environments