SSenStone is a South Korean authentication security company founded in 2015, with its global headquarters (operating as swIDch) established in London, UK in 2018. The company develops and commercializes authentication technologies centered on its proprietary OTAC (One-Time Authentication Code) technology — a unidirectional, dynamic authentication code system designed to secure identification and authentication between humans and devices, as well as device-to-device communication. The company's core product portfolio includes the swIDch Auth SDK, OTAC Token, and OTAC Trusted Access Gateway (TAG), along with OTAC auth - MFA for PLCnext, which extends multi-factor authentication to programmable logic controllers (PLCs) used in operational technology (OT) environments. SSenStone also offers OTAC for Phygital, a solution bridging physical and digital authentication contexts. SSenStone targets a range of sectors including financial services (supplying OTP technology to banks such as Toss Bank), industrial control systems, IoT devices, and government/public sector entities. The company has supplied its OTAC technology to clients such as the Indonesian Tax Service and has conducted proof-of-concept projects with automotive and industrial firms including Continental Korea and LS ELECTRIC. The company holds over 210 registered global patents and 390+ intellectual property rights. It has received multiple international recognitions including the CyberSecurity Breakthrough Award for authentication and fraud prevention, SC Awards Europe for IoT/IIoT security, and was designated a Hot Company in PLC Security at RSAC 2025. SSenStone is also certified under FIDO2 international standards and has obtained CC and GS certifications for its software products.