PortalGuard is a contextual authentication platform that provides single sign-on, password management, two-factor authentication, and real-time reporting capabilities. It offers a tokenless two-factor authentication approach that sends one-time passwords (OTPs) to users' mobile phones via SMS, email, or transparent tokens. The authentication process involves a user entering their username, being sent an OTP, entering both the OTP and their password, and gaining access if authenticated. PortalGuard is configurable by user or group and supports RADIUS for VPN authentication with network devices in a multi-step process. It has technical requirements including .NET framework and specific Windows and IIS versions.