Duress code A duress code is a covert signal used by an individual that is under duress to indicate their state . The term duress code typically refers to a signal embedded in normal communication , such as a word or phrase used during conversation to alert other personnel of the duress . Alternatively , the signal may be incorporated into the authentication process itself , typically in the form of a panic password , distress password , or duress PIN that is distinct from the user ' s normal password or PIN . These concepts are related to a panic alarm and often achieve the same outcome . Civilian usage . Some home and property alarm systems have duress PINs , where the last two digits of the reset code are switched around . Entering the code when under duress from an assailant can trigger a silent alarm , alerting police or security personnel in a covert manner . The implementation of this feature has not been without controversy , as it has been claimed to lead to false alarms . A similar mechanism , SafetyPIN , has been proposed for use in ATMs . In 2010 , the Federal Trade Commission issued a report studying the viability of such mechanisms for ATMs . They noted duress PINs have never been actually implemented in any ATM , and conclude that the costs of deployment outweighs the likelihood they will actually deter criminal activity . When a duress PIN is used to trigger a silent alarm , an adversary can always request the PIN in advance and ensure the appropriately modified PIN is entered instead . If the adversary does not know which PIN is correct , they may choose randomly between the two possible codes allowing them to succeed half of the time . In scenarios where a panic password is used to limit access control , instead of triggering an alarm , it is insufficient to have a single panic password . If the adversary knows the system , a common assumption , then he will simply force the user to authenticate twice using different passwords and gain access on at least one of the two attempts . More complex panic password schemes have been proposed to address this problem . For cases where verbal communication ( i . e . via cell phone ) is possible with family member or friend , a covert phrase can be used to signal duress . In the slim chance that a captor allows the person in duress to use their cell phone ( i . e . to obtain a PIN ) , there is a limited opportunity to use a duress code . Because conversations are often being monitored by a captor , they must be subtle and short . Ideally , the use of a duress code has been confirmed before the current situation , so the family member or friend has verifiable evidence that something is wrong , and when the authorities are notified aren ' t just limited to speculation . Examples would include asking about someone who does not exist . For example , " What is Cindy barking at ? " when the person on the other side knows that either there is no dog , or dog ' s name is Maggie . In addition to a duress code , there is duress activity . This may include the duressed individual withdrawing cash from an ATM using a specific credit card , instead of using their debit card . Many credit card companies allow for email alerts to be set up when specific activity occurs . There are technical issues that could pose problems , such as a delay in notification , cellular network availability , and the fact that a location is not disclosed , only the activity . Civilian and commercial aircraft can use the Transponder Code 7500 as a duress code to indicate hijacking . Military usage . A simple but effective duress code used over the telephone by SOE agents in occupied Europe during World War II was to give a coded answer when someone checked whether it was convenient to visit a safe - house . If it was genuinely safe to visit , the answer would be " No , I ' m too busy . " However , if the safe - house had been compromised ( i . e . the Nazi s had captured it , forcing the occupants to answer the phone at gunpoint in order to lure in other members of the SOE network ) the captured agent would say " Yes , come on over . " Having been warned that the safe - house had been compromised , the other agent would hang up the phone and immediately inform his team - members so that they could take appropriate action . Typically , this meant using escape and evasion procedures , before the captured agent was tortured by the Gestapo and forced to give incriminating information such as names and addresses . References in popular culture . The concept of duress codes is used in fiction , particularly in spy fiction . In the fourth episode of the fifth season of " 24 " , hostage and CTU operative Jack Bauer used the phrase " flank two " as a duress code . In the 2007 film " The Bourne Ultimatum " , CIA field officer Nicky Parsons is given the option of using a panic password when communicating with headquarters . In the " " episode " " , James T . Kirk gives the Duress Code " Condition Green " , implying to his captors that all is well ( compare " Condition Red " ) , but to his crew that he had been compromised and that it was too dangerous to mount a rescue attempt . In the TV series " Chuck " episode " Chuck Versus the Nemesis " , Morgan refers to the duress word " pineapple " . Chuck eventually uses this word to inform Morgan of his danger when he is captured by a Fulcrum Agent .