challenge and response

During Operation Overlord soldiers were trained to use a "challenge and response" system in order to identify friendly forces in situations were they could not make visual contact.

Captain Miller's Ranger squad used this system while passing through the town of Neuville during their search for Private James Ryan.

First Army Passwords

Day Challenge Password June 6 D-Day flash thunder June 7 D+1 thirsty victory June 8 D+2 thirsty victory June 9 D+3 thirsty victory June 10 D+4 weapon throat June 11 D+5 weapon throat June 12 D+6 weapon throat June 13 D+7 wool rabbit June 14 D+8 wool rabbit June 15 D+9 wool rabbit