If your clients have certificates, consider using client certificate authentication
Jason Taylor, Prashant Bansode, Carlos Farre, Madhu Sundararajan, Steve Gregersen
Client certificates can authenticate a client service account or multiple users to a WCF service. If you use a client certificate for each user, you can map each certificate to a Windows account.
The certificate to Windows account mapping feature is enabled in the service configuration file as follows:
<authentication mapClientCertificateToWindowsAccount="true" />