Cybersecurity defence companies in Denmark

Danish quantum communications company building QKD systems for quantum-secure key exchange over existing fibre networks, including defence and government deployments.

Develops laser-based quantum random number generators (QRNG) for encryption and secure communications. A DTU spin-out founded in 2022, it builds on more than 20 years of quantum communication research at the Technical University of Denmark.

Builds the Arbit Data Diode and Trust Gateway for cross-domain network segmentation, certified to Common Criteria EAL7+ and accredited for NATO COSMIC TOP SECRET and EU TOP SECRET data transfer. Founded in Hvidovre in 2006.

Arbit Data Diode 10 GbE

Hardware data diode that moves data from an open network into a closed one over a single fibre-optic link that can only send light in one direction, with two dedicated servers acting as sender and receiver. It supports mail, file shares, FTP, REST and video or radio streaming, and is certified to Common Criteria EAL7+.

Arbit Trust Gateway 10 GbE

Gateway for exporting data from high to low security networks, built to replace manual transfers by USB stick. Two data diodes in series create an isolated zone that holds configuration and program code as read-only, and the gateway checks content, authenticates the source and can require approval from a releasing officer.

C4ISTAR Gateway

Cross-domain gateway for importing and exporting data between security domains, sold in a server room version and a ruggedised version with NATO standard connectors for vehicle mounting. It supports NATO releasing and clearing officer functions, signature checks, SitaWare integration and national security profiles that customers can build themselves through an open API.

Brøndby company that makes Dencrypt Connex, end-to-end encrypted voice, video and messaging for defence, government and business users. Terma agreed to acquire it in August 2026.