Tap Code Cipher | Pocket Sized Encryption Device
Tap Code Cipher | Pocket Sized Encryption Device is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Delivery and Shipping
Delivery and Shipping
All standard orders normally ship within 1 business day.
Custom orders normally ship within 2 business days.
Description
Description
The tap code, sometimes called the knock code, is a way to encode text messages on a letter-by-letter basis in a very simple way. The message is transmitted using a series of tap sounds, hence its name.
The tap code has been commonly used by prisoners to communicate with each other. The method of communicating is usually by tapping either the metal bars, pipes or the walls inside a cell.
Note that this system is not limited in usefulness to just tapping sounds. I could be used at night by flashlight code or in a field or ship to shore by flag waving or even ht in hand waving.
The tap code is based on a Polybius square using a 5×5 grid of letters representing all the letters of the Latin alphabet, except for K, which is represented by C.
Each letter is communicated by tapping two numbers, the first designating the row and the second (after a pause) designating the column. For example, to specify the letter "B", one taps once, pauses, and then taps twice. The listener only needs to discriminate the timing of the taps to isolate letters.
The letter "X" is used to break up sentences, and "K" for acknowledgments.
Because of the difficulty and length of time required for specifying a single letter, prisoners often devise abbreviations and acronyms for common items or phrases, such as "GN" for Good night, or "GBU" for God bless you.
By comparison, Morse code is harder to send by tapping or banging because a single tap will fade out and thus has no discernible length. Morse code, however, requires the ability to create two distinguishable lengths (or types) of taps. To simulate Morse by tapping therefore requires either two different sounds (pitch, volume), or very precise timing, so that a dash within a character (e.g. the character N, ▄▄▄ ▄ ) remains distinguishable from a dot at the end of a character (e.g. E-E, ▄ ▄ ). Morse code also takes longer to learn.
Learning the tap system simply requires one to know the alphabet and the short sequence "AFLQV" (the initial letter of each row), without memorising the entire grid. For example, if a person hears four knocks, they can think "A... F... L... Q". If after a pause there are three knocks, they think "Q... R... S" to arrive at the letter S.
To view a video on this cipher, copy and paste this link
https://youtu.be/q4lI6_V6SqA
Materials: Wood
Personalize it!
Personalize it!
Click YES above the quantity selector to add a personalized laser engraving to your puzzle or game.
- Perfect for gifts
- Business marketing opportunity
Recommended age group
Recommended age group
Difficulty level
Difficulty level
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Personalize It!
Did you know we can add a custom laser engraving to every puzzle and game? Well, we can. Add a personal touch to your gift with a name or message.

Collections for you
Frequently Asked Questions
Shipping
What countries do you ship to?
What countries do you ship to?
We ship all around the world. If you encounter an issue at checkout, please use the Chat Box to contact us. A real person will assist you.
How long will it take to receive my order?
How long will it take to receive my order?
Standard shipping normally takes 3-5 days. Next-day shipping is available on all domestic orders (for an additional charge). International shipping times vary depending on the product and destination (estimated at checkout).
Expedited shipping is available at checkout.
Returns and Refunds
How do I return a product?
How do I return a product?
Items must be returned within 30 days after receiving your order. Items must be returned in the same condition in which they were received, be unworn/unused, have any tags still attached, and include all the original packaging.
Custom/Personalized items can only be returned if we made a mistake on the customization/engraving.
How long will it take to receive my refund?
How long will it take to receive my refund?
Refunds are processed within 7 days from when we receive the item(s).