StrongKey FIDO Server (SKFS) has the ability to return either a Json Web Token (JWT) or Security Assertion Markup Language (SAML) assertion to be used for single sign on. These are configurable options in the SKFS and can be configured on a per site basis to include these with the authenticate response.

SKSO uses the JWT returned by SKFS for the user authentication state management. Enable it by modifying the configuration property for SKFS.

Please refer the link on how to enable SAML on the FIDO server.