OpenOTP Two-Factor Authentication

It is versatile, device-independent and based on opened security standards.
OpenOTP provides fine-grained user identity and access management (IAM), one-time passwords authentication technologies (OTP), Universal Second Factor (U2F) and extensive authentication policies for your AD / LDAP users.
It is enterprise-ready with strong support for high-availability, load-balancing, multi-tenancy, cloud-readiness, geolocalization, delegated administration and much more.