Journal spreadsheet upload - technical issue

While Uploading a Journall through spreadsheet user have to give there userid and we have greyed out the password field and put the default password of all the user

since the default password of all the user is same, any user can upload the journal by using somebody else's id

for example User U1 is having same password as User U2 than U1 can upload a journal using Id of U2

in order to prevent this, if we get the user name from user's windows machine and compare it with his peoplesoft id, if it is not equal , we should stop the user