[palani]

passport c.1500, from M.Fr. passeport "authorization to pass through a port" to enter or leave a country (15c.), from passe, imper. of O.Fr. passer "to pass" + port "port."

Whose authorization do you need to pass through a port? Why do you need the authorization of a 3rd party to travel?

visa 1831, "official signature or endorsement on a passport," from Fr. visa, from Mod.L. charta visa "verified paper," lit. "paper that has been seen," from fem. pp. of L. videre "to see" (see vision). Earlier visé (1810), from Fr. pp. of viser "to examine, view."

Whose country is your nation at war with?

LICENSE, International law. An authority given by one of two belligerent parties, to the citizens or subjects of the other, to carry on a specified trade.

2. The effects of the license are to suspend or relax the rules of war to the extent of the authority given. It is the assumption of a state of peace to the extent of the license. In the country which grants them, licenses to carry on a pacific commerce are stricti juris, as being exceptions to the general rule; though they are not to be construed with pedantic accuracy, nor will every small deviation be held to vitiate the fair effect of them.