Atsign

Networking technology that removes open listening ports so devices cannot be scanned or directly attacked.

Atsign's protocol lets devices and services communicate through outbound-only, end-to-end encrypted connections, leaving no open ports for attackers to find. It suits IoT fleets, remote access, and infrastructure that should be invisible to internet scanning. The company was founded in 2019 and offers open source SDKs.

Category: PKI, Crypto & Quantum
Founded: 2019
Funding: $11M raised (Seed, 2021)
Website: https://atsign.com

Seen at Black Hat USA 2026 (Startup City sponsor, booth 5901).

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