SPI-13: Configure a service to use high-assurance X.509 certificates for user access

Executive Summary: 
A service provider needs to configure a service to allow or require a high-assurance X.509 certificate for user access so that the user authentication process is assured to satisfy the IGTF “MICS/BIRCH” level of assurance.
User Importance Summary: 
Some resources within a public research computing community may be important enough to merit enhanced security measures, such as high assurance user credentials. Service providers need mechanisms for using these credentials to enable user access.
Target Communities and Sizes: 
Service providers - 10 < N < 100