Q:

how to match between a user in asp.net and a user in sharepoint

i need a asp.net function that takes username and password and a sharepoint link and return true if the username and password match a user in sharepoint
i try make an object from spuser and check login name but still need to check user password
but spuser gives me all info about users except its password :(
actually i don't want to change any data in sharepoint ,i need only to know if there is a user have the same username and the same password in sharepoint
thanks in advance

A:

What authentication is being used in SharePoint? If it is Windows Authentication then it is not possible to get the password, as the password hash will be stored in Active Directory. There is no way to get the password. 
However, you can validate if the user/password combination is correct.
Use the 

System.DirectoryServices.AccountManagement

namespace to query the AD
Check this post on how to do it. link

