BlastShield is a zero-trust, software-defined perimeter solution designed to protect critical IT and OT assets by rendering them invisible and inaccessible to unauthorized users. It establishes an encrypted, peer-to-peer overlay network that cloaks protected devices and data from network scanning or traffic analysis tools, preventing credential theft, reconnaissance, and lateral movement. BlastShield combines phishing-resistant, passwordless multi-factor authentication (including mobile authenticators or FIDO2 keys), microsegmentation, data-in-motion encryption, and policy-based access controls to ensure only explicitly authorized devices and users can connect. It supports deployment across a wide range of network environments, TCP/IP, SCADA, SD-WAN, or even raw Ethernet, and can protect everything from legacy OT/ICS equipment, sensors, PLCs, HMIs, cloud VMs, and virtual infrastructure.