Crosslayer Labs

Protect, monitor and defend your Internet presence

Y CombinatorWinter 2026ActiveB2BSecurity

What they do

Problem

Organizations are vulnerable to impersonation and hijacking attacks across their websites, APIs, and Internet dependencies without clear, actionable visibility into the root cause.

Solution

Crosslayer Labs provides outside-in monitoring that discovers and correlates signals across DNS, BGP, TLS certificates, and JavaScript to detect impersonation attacks and deliver actionable alerts with remediation guidance.

Who it's for

Security and infrastructure teams at organizations operating Internet-facing websites and APIs, especially enterprises.

Founders

Henry Birge-Lee

Founder

I am am innovator in web and network security. I invented Multi-Perspective Issuance Corroboration (MPIC) which now secures every single HTTPS connection. I am currently focusing on building the Crosslayer Labs platform for web resource integrity.

Grace Cimaszewski

Founder

I'm a recent PhD graduate from Princeton and security researcher. I've worked with the CA/Browser Forum to turn my research on TLS certificate security into ecosystem-wide requirements which now improve the security of every HTTPS connection you view in your browser. Before starting Crosslayer with my long-time research collaborators, I was a visiting research at Google and Corelight Labs.

Prateek Mittal

Founder

I am a professor at Princeton University and co-founder of Crosslayer Labs (YC W26). I specialize in the field of cybersecurity/privacy and am the recipient of the ACM Grace Hopper Award. My research has helped secure every single web connection (HTTPS) worldwide and enhanced the security of deployed LLMs (e.g., GPT 3.5 and GPT4V at OpenAI).

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