How to authenticate a asp.net application user to share point site

In our organisation we published a asp.net mvc application in internet , and other side

also we have a share point internet portal.

for asp.net mvc application :

here every authenticated user login to asp.net mvc application ,

every registered user and authenticated user stored in sql server database.

for share point :

share point application has enabled claims authentication and not allow anonymous log in for users

and a specific group of active directory users only has permissions to view this share point portal.

Here in mvc application there is a service to view the some BI data and this data is in sharepoint web application

here how i connect authenticated mvc application user to view the BI data in sharepoint?