Unexpected Error: System.Security.Cryptography.CryptographicException in Sharepoint 2010

Chances are, you encounter this kind of error while setting up a Project Server 2010 during the creation of Project Web Access site.

After I successfully created my PWA site and bid my chance to access it in the client machine, when I discover this error:

To pinpoint the actual location and cause of error, I use ULS Viewer and filter out the prompted Correlation ID.

Solution:

When users try to access Web services, the security permissions might not be set correctly for the MachineKeys directory (C:\Documents and Settings\All Users\Application Data\Microsoft\Crypto\RSA\MachineKeys) on the application-tier server.

The service account must have full access to the MachineKeys directory on the application-tier server. If service account does not have full access, you should update the permissions for that directory.

If your configuration is using impersonation or using the IUSR_MACHINENAME user, then configure the MachineKeys folder sercurities and give the user Read & Execute, List Folder Contents, Read, Write. If that doesn't work, try giving the Everyone user the same permissions.