Graphical identification and authentication (GINA), used for secure authentication and interactive logon has been replaced by Credential Providers. Combined with supporting hardware, Credential Providers can extend the operating system to enable users to log on through biometric devices (fingerprint, retinal, or voice recognition), passwords, PINs and smart card certificates, or any custom authentication package and schema third party developers wish to create. Smart card authentication is flexible as certificate requirements are relaxed. Enterprises may develop, deploy, and optionally enforce custom authentication mechanisms for all domain users. Credential Providers may be designed to support Single sign-on (SSO), authenticating users to a secure network access point (leveraging RADIUS and other technologies) as well as machine logon. Credential Providers are also designed to support application-specific credential gathering, and may be used for authentication to network resources, joining machines to a domain, or to provide administrator consent for User Account Control. Authentication is also supported using IPv6 or Web services. A new Security Service Provider, CredSSP is available through Security Support Provider Interface that enables an application to delegate the user's credentials from the client (by using the client-side SSP) to the target server (through the server-side SSP). The CredSSP is also used by Terminal Services to provide single sign-on.