This is the 14545th most frequent Russian word.
паспортом
The instrumental case of "паспорт," meaning "passport" (used as "with/by a passport").
In this sentence, 'паспортом' is the instrumental case of 'паспорт', indicating the means by which the action of verifying identity was performed.
Я подтвердил свою личность паспортом.
I verified my identity with a passport.
Here, 'паспортом' indicates the required condition or object ('passport') needed to perform the action (entering the hall).
Войти в зал можно только с паспортом.
You can enter the hall only with a passport.
'Паспортом' is used to specify the instrumental case to imply what is needed or used during a procedure (check-in for the flight).