Challenge & Password for The Prepared Family, by A. Jackson

One of the best ways to improve your preparedness skills is by adapting military skills to preparedness uses. Today we’re adapting the U.S. Army Common Task of ‘Challenge & Password’ to the needs of the survivalist.


Consider the following scenario: About six weeks ago it finally happened, the currency collapsed and since then the security situation has rapidly deteriorated. Crime has begun to run rampant as the populace grows more and more desperate to fill their and their family’s bellies. At some point most of the local police force realized that their entire paycheck couldn’t even buy their family a single loaf of bread and every minute they spent protecting your family was one that put their own at risk. The few police that are reporting for duty can’t adequately keep the security situation from spiraling out of control. You’ve been up the last 20 hours warning strangers away from your home and watching for the friends you expect to come shelter with you for the duration of the difficulties. You pray that they arrive soon because you’re not sure you can stay awake much longer and the moon will soon set… dropping the neighborhood into total darkness now with the rolling blackouts. Finally, you see the outline of three people headed directly for your home…your friends must have picked up another along on the way. It sure looks like Jim and Carol walking in and all you need to do to confirm it is hear their voice, so you call out. “Who’s there?” and receive the expected reply “It’s me.” With great relief you step out from your hide and walk up to greet them you soon discover are strangers. Your last thought before you lose consciousness is: “she sure sounded like Carol.”

Challenge & Password is a one technique used by military forces to recognize friendly forces in hostile environments or while guarding resources. While the need for such a technique when encountering a soldier from an adjacent unit that you haven’t met before is apparent this technique also assists service members in recognizing friendlies in low light and no light situations. You may believe that you will always recognize those you should let in and easily identify hostiles but in reality, it’s very easy for a tired and hopeful mind to ‘see’ what it hopes or expects to see when the reality is something else entirely. Challenge & Password and the other recognition techniques we’ll explore today are meant to verify what your eyes and ears are telling you to ensure that those really are friendlies walking up on your position.

Challenge & Password

Challenge & Password is nothing more than a sign and countersign that let’s two parties recognize each other as friendlies. Here’s how it works:

  1. The stationary party sees and/or hears the traveling party walking up on his/her position and observes until the other party is vulnerable in the open and within voice range then calls out “HALT” just loud enough to be heard by that party but not so loud as to broadcast the stationary party’s position to the four corners of the Earth. This command should be called out from a position of safety where you can cover the other party with any weapons you may have. At this point the other party takes one of several actions that telegraph their intentions, but the most likely results are that they run, they fight, or they halt. If the traveling party halts and you think those you’ve addressed are friendlies then continue with the procedure, otherwise warn the traveling party off continuing into the area you are securing. You might tell such a party “Private property ahead, turn back now” for instance.
  2. If the other party halts you should command the party to lower their weapons or take other actions as required to assure your safety before directing one member to “ADVANCE AND BE RECOGNIZED.” During this entire procedure make sure to continually observe the other party and your surroundings for your own and your family or party’s safety. Additionally, make sure to use a clear, commanding voice when giving these instructions…do not show weakness or hesitancy.
  3. Once the indicated person has advanced far enough that you can easily talk with him or her in a low tone that doesn’t carry to hidden watchers you once again command “HALT.”
  4. At this point you present the Challenge in a low voice. For this example, we’ll use the Challenge, ‘Thrifty’ and the Password, ‘Flower.’ As mentioned, in a low voice you clearly Challenge, “THRIFTY” and wait for the response. Any response but ‘Flower’ indicates that this is not your party and should be sent on their way. A proper response allows you to bring the person in.
  5. If there are multiple members of the party entering your area, then have the person you have vetted individually identify and bring in each person to make sure that there are no straphangers.

Note that a Challenge & Password should be two words that are unrelated and form an unusual but memorable phrase. Words that are unlikely to be used together. ‘Thrifty Flower’ is a great example of how a Challenge & Password should work but ‘World Series.’ ‘Puddle Jumper’ or ‘Fig Newtons’ are examples of poor choices because there is a chance that an unknown party could guess the proper password response. Below are a series of words that could be combined to form properly unusual phrases for your Challenge & Password.

Challenge & Password combinations should be changed on a set schedule once usage becomes commonplace and necessary. Determine the schedule based on the security situation in your area.

The following are 10 examples of Challenge & Password options. Mix and match to your heart’s content or invent your own, just make sure they are words that don’t typically go together.  (Thus, the challenge “New York” and the password “Yankees” would be a very poor choice.)

Challenge Password
Iron Flower
Jackson Farming
Lousy Carnival
Purple Oldsmobile
Sandwich Fixture
Fifty-Five Mistletoe
Book Cardinal
Hot Tub Desert
Shetland Helicopter
Copious DaVinci


The Running Password

As you can surmise by the description of the Challenge & Password procedure above…it takes a while to do it right. If you’re being chased and need to get to safety quickly you use the ‘Running Password.’ There is no time for subtleties when you are running for your life so as you run across the security perimeter you shout the Running Password to make sure that the friendlies aren’t surprised by your sudden arrival, know you’re a ‘good guy’ and are prepared to help you deal with whatever threat has you on the run.

Needless to say, make sure to keep an eye out for tailgaters following and mimicking your guy or group running into your perimeter yelling the Running Password. Additionally, make sure to change the Running Password as soon as reasonable after they’ve been used.

10 Running Password Options:
Tiger Lilly
Rachel Welch

Now that we’ve discussed the use of both Challenge & Password and the Running Password let’s explore some other potential recognition codes for use in a security compromised environment. 

Noise or Knock Signals

In Matthew Bracken’s near future novel, Enemies Foreign And Domestic, the protagonists gain entry to the bad guy’s rec room by mimicking the distinctive knock that the bad guys were using as a recognition code to gain entry. Loudly knocking out ‘Shave and a haircut’ wasn’t very effective for the bad guys. However, I can foresee certain situations where a noise or knock code would be an appropriate recognition signal.

Two places I can imagine a knock code being useful are if you are forced to shelter in an apartment or an industrial area. In an apartment where multiple groups and families have access to common areas like hallways, your security perimeter by necessity, may have to be your own four walls and door. In an industrial area you may also have to limit your security perimeter to the four walls if there’s not a more appropriate perimeter like a security fence or you have limited personnel to secure your building.

In designing a recognition code from knocks, make sure to knock as lightly as practical so as to reduce the chance of being overheard. Additionally, I recommend using a mathematical code to reduce the likelihood of the bad guys figuring out how to get in and allow each party to recognize that the other is the desired party. Here’s how it works:

  1. The party outside knocks in four knock increments by prior arrangement. Think of this as announcing the outside party’s presence.
  2. The inside party responds with 2-5 knocks (randomly chosen). Let’s say 2 knocks in our example. This is the Challenge.
  3. The outside party responds with one less knock than the inside party used. For instance, if the inside party knocked three times than the outside party responds with (3-1) 2 knocks. This is the Response.
  4. If you want to make sure that the inside party is who the outside party expects you could add another Response by adding or subtracting one knock from the previous Response.

It’s important to keep in mind while telegraphing your location by knocking that most walls and virtually every door are permeable to shots fired of sufficient caliber and powder charge.

Panels or Flags

An interesting recognition system that we tested while I was in the 82nd Airborne Division (we used them for reconstitution after a jump) were panels. By using placards or flags you can signal a simple message like “friendlies here,” “DANGER,” “meet here” or “meet at X.”

Panels used in this manner do lack the Challenge and Response mechanism of the other techniques we’re discussing but may serve a useful purpose and maritime military units have historically used flags for Sign and Countersign (Challenge & Password) at sea.


One if by land and two if by sea may be familiar to you from Henry Wadsworth Longfellow’s poem, “Paul Revere’s Ride” and demonstrates the successful use of lights for signaling but lights present problems when used as recognition codes because they can be seen so well over great distances at night. If you do determine that you must use lights for recognition codes, I recommend using directional lights (flashlight, not lantern) and a mathematical code as described in Knock Signals above or perhaps the use of distinctive colored lenses to make mimicry less likely or successful.

Duress Codes

An interesting addendum and safety mechanism that can be added to any of the techniques discussed above is the addition of a Duress Code. A Duress Code signals to the other party that the person signaling is under duress and being forced to make the contact under threat. A Duress Code allows the party not under duress to be ready and trap the bad actors who are coercing one of our friendlies to make entry. A Duress Code could be a word, a phrase, a series of knocks, ‘body language,’ or a particular color of light. Duress Codes could also be outgoing to warn a party coming into a presumed safe area and could be signaled by a light in a particular window, a flag or panel or some other noticeable change in the environment that will only have meaning to those parties ‘read into’ the code.

I’ve used the concept of the Duress Code with all of my daughters whereby they could call us and utter an innocuous code phrase and we would drop everything and come retrieve them from whatever mischief their friends had in mind. My daughters could extract themselves from unsavory or dangerous situations without losing face with their peers and blame their desertion on their overly protective Dad.


Listed above are some of the considerations and mechanisms of practical implementation of a Challenge & Password system. Proper implementation of a Challenge & Password system may not only save your life but may also save the lives of those closest to you. Take some time to think about how you would implement such a system now so that you could rapidly transition to using a system if you needed one… better yet, discuss the system with your family or group and practice it’s use. Just remember as you develop your systems that there’s no need to reinvent the wheel, learn from what has worked for military forces throughout history like U.S. Army Common Tasks Skill Level 1 Task “Challenge & Password.”

About the Author:

Andrew J. Jackson is a married father and entrepreneur working as a risk manager from a small town in America’s heartland. He has over three decades of military experience beginning with an active duty stint as an 11B (Infantryman) in the 82nd Airborne Division and finished his career as a field grade Military Intelligence Officer in the Army Reserve. He is the Editor of


  1. Interesting, we had a code word when my child was small and didn’t want to do something another child had suggested, like a sleepover, we would have them say “I GUESS” I could stay overnight with them couldn’t I Mom? The “I GUESS” was my signal to be the Bad Mom and say no you can’t, then my child could go back to the other child and say I can’t, My Mom won’t let me, without hurting the other child’s feelings.

  2. In this current world of scams, (a person calling gramma or grampa for money because they are in jail, car wreck, cash stolen while on a trip, or any number of problems,) having prepped family members with passwords is a very good idea. Convincing a teen that this is necessary may strain your diplomatic skils.

  3. I have read stories where a wife’s purse and cell phone are stolen and the thief uses the cell phone to text the husband for the ATM card pin code. Rule #1 lock you phones. Two always have an agreement that if such info is needed it is done via phone call

  4. Reminds me of the clickers (crickets) they used during the D-day invasion. The only drawback is, you’d need to carry it with you at all times…
    Although I see there are several web sites that sell replicas.

    1. Not sure what happened with my last comment but you can buy dog training clickers at the national pet stores. They can even be put on a keychain. The store I looked at had them from $1.49 up to $4.99. Considering how big they are leaving one on your keychain seems like a win win.

  5. In the Army, we use challenge and passwords, but they aren’t used alone. You use them in sentences and in as natural language as you can, the duress signal as well. If someone is with you that isn’t pleasant company, you don’t want them to know you are exchanging a challenge and password or duress code. You might also have an unfriendly nearby unaware to you listening, don’t make it easy for them to overhear your challenge and password.

  6. Would use code words with my sons. “ I love you” was substituted with – guess what? I could say guess what? And they knew what I ment without buddies laughing.. to this day I hear guess what and know what they mean. I even hear it from their friends. I guess they shared the code.

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