AI Security Researcher/Research Engineer in London

Remote or hybrid - London preferred

About Brave: Brave is on a mission to protect the human right to privacy online. We’ve built a free web browser that blocks creepy ads and trackers by default, a private search engine with a truly independent index, private AI assistant, latest privacy and security features, and a private ad network (opt-in!) that directly rewards you for your attention. Already over 120 million people regularly use Brave for a faster, more private web. Millions more switch every month. The internet is a sea of ads, hackers, and echo chambers. Big Tech makes huge profits off our data, and tells us what’s true and what’s not. Brave is fighting back. Join us!

Summary: We are looking for a researcher/research engineer to help mitigate the security risks that come with building AI systems - especially LLM-powered web agents and chatbots. In this role, you'll design and implement secure-by-design architectures, audit our LLM-powered web agent and chatbot, and help set Brave's direction on how we identify, measure, and reduce security risk across AI products.

Responsibilities:

• Design and execute adversarial evaluations to uncover failure modes in LLM-powered web agents and chatbots (e.g., prompt injection, tool abuse, data exfiltration)
• Analyze model behavior (including internal thoughts) to understand and forecast security risks in frontier models
• Develop and prototype security-focused training and fine-tuning techniques
• Augment web agents with security principles including information flow control, privilege control and contextual security
• Partner with engineers and (privacy, ML, and Cryptographic) researchers to translate findings into product changes, tests, and measurable security improvements
• Help define a forward-looking security strategy and policy for building and responsibly releasing web agents—advocating for user protection

You may be a good fit if you have:

• Demonstrated experience working on Secure AI (prompt injection attacks and security guardrails)
• Strong publication record in AI security, ML security, or closely related areas
• A track record of shipping products and features inside a fast-moving environment
• Strong coding skills in Python and familiarity with ML frameworks like PyTorch or JAX
• Experience training, fine-tuning, and evaluating large language models
• Deep familiarity with large language models and web agents, how they work, and how they are trained
• Experience applying security principles (e.g., information flow control, access control/least privilege)
• Demonstrated success in bringing clarity and ownership to ambiguous technical problems
• A Ph.D. in computer science is highly preferred, but we may consider some exceptions with industry experience

Skills That Will Set You Apart from the Competition:

• Knowledge of AI Systems (pipelines, security evaluation, etc.)
• Open source projects on security/privacy
• Experience with confidential computing and ZKP/SMPC protocols
• Ph.D. in computer science from a top-tier school
• A strong publication record in premier systems, performance, or ML
• Work experience in industry is desirable

Working at Brave - What we offer:

• Ability to work at an exciting and well-funded international startup headquartered in San Francisco
• Cutting-edge technology, allowing you to work with state-of-the-art tools and software solutions
• Competitive compensation and plenty of room for personal growth
• Great international exposure and team atmosphere

We are looking to hire in London but would consider an exceptional candidate in the rest of Europe.

NO AGENCIES or RECRUITERS PLEASE - Unfortunately, we cannot work with third parties on these searches.