Softminer.net

TO get sid of a user, wun following command:

wmic useraccount where name="USER" get sid
wmic useraccount get name,sid

in C# can check user UserSid:

var me = WindowsIdentity.GetCurrent();
SecurityIdentifier sid = me.User;

To get Group Policy of a user in domain use

gpresult /r

More info about gpresult