Secret messages in Morse code for friends and family
A message in Morse code is not secret on its own. Morse is a code, not a cipher: every letter has one published pattern, the same everywhere, so anyone with a chart can read what you wrote. To make a Morse message feel secret, do one of two things: hide the fact that it is Morse at all, in knocks, a blinking light or a drawing, or scramble the letters with a simple cipher first and send the scrambled text in Morse.
Both are games, not security. They are perfect for a note in a lunchbox or a signal across the garden, and wrong for anything that truly needs to stay private.
Code or cipher: why anyone can read Morse
A code swaps each letter for a fixed symbol and the table is public. International Morse is set out in an ITU standard, ITU-R M.1677-1, and the same table is printed in books, on posters and on the back of activity sheets. A is .- for you, for your neighbor and for a ship’s officer. Nothing about the pattern depends on a key that only you and your friend know.
A cipher is different. It scrambles a message with a rule or a key you agree in advance, and without the key the result is nonsense. That is the part Morse lacks.
What Morse does give you is privacy by obscurity. Someone who glances at -- . . - / .- - sees dots and dashes, not MEET AT, and most people will not bother to fetch a chart. That is enough for a family game. It is not enough to stop anyone who decides to look.
Hide the Morse in plain sight
The fun of a secret message is that nobody notices it is a message. A few ways to tuck Morse into ordinary things:
- Knocks and taps. A knock has no length, so you cannot make a long one. Agree on two sounds instead: a light fingertip tap for a dit and a firm knuckle knock for a dah, with a clear pause between letters. A family knock that spells one letter, say F
..-., at the bedroom door is a password only the family can read. Tapping and blinking Morse code without any equipment has more ways to send it with your hands. - A light. A flashlight, a desk lamp switched on and off, a phone’s light: a short flash for a dit, a flash three times as long for a dah, darkness between. Point it at a wall or a window, never into anyone’s eyes. How to signal Morse code with a flashlight covers the timing.
- A drawing. A fence with short and long pickets, a path of round and long stones, rain falling as drops and streaks, a border of dots and dashes around a birthday card. Leave a slightly bigger space between letters than between the parts of a letter, and a bigger one again between words, or nobody can read the picture.
- Objects. A row of buttons and matchsticks on a windowsill, round and long beads on a bracelet, stitches along the edge of a bookmark.
- An ordinary sentence. Agree that a word of three letters or fewer is a dit, a longer word is a dah, and a period ends a letter. Then “See you at six. Go now.” is four short words and two short words: H
....and I.., which spell HI. It reads like a reminder and carries a greeting.
Every one of these still uses the plain Morse table. They fool people who are not looking, not people who are.
Add a simple cipher underneath
For a message that a curious sibling with a chart still cannot read, scramble the letters first, then put the scrambled text into Morse. The receiver decodes the Morse into letters, then unscrambles them.
The classic is a shift cipher, often called a Caesar cipher: move every letter a fixed number of places along the alphabet. With a shift of 1, A becomes B, B becomes C, and Z wraps around to A.
| Step | Message |
|---|---|
| Plain text | MEET AT SIX |
| Each letter shifted by 1 | NFFU BU TJY |
| In Morse | -. ..-. ..-. ..- / -... ..- / - .--- -.-- |
To read it, the receiver turns the Morse back into NFFU BU TJY, then moves each letter back by one. Agree the shift face to face, never in the same note as the message.
Two more tricks that sit well under Morse:
- Write each word backwards before you encode it. TEA becomes AET, and a reader who decodes the Morse gets letters that look like a mistake.
- A keyword alphabet. Write a keyword with no repeated letters, follow it with the rest of the alphabet in order, and line that up under the normal A to Z. Each letter of your message swaps for the one under it. Both of you need the keyword.
Be honest with yourselves about the limits. A shift cipher falls to anyone who tries all 25 shifts, and a keyword alphabet falls to anyone patient enough to count which letters turn up most. These are puzzles for people you like, not protection for passwords, addresses or anything private. For that, use something built for privacy, not Morse.
Writing it down so it can be read
Secret or not, a Morse message only works if the receiver can tell where each letter ends. On paper:
- Leave one space between letters and a slash between words:
.... ..is HI, and.... .. / -- --- --is HI MOM. - Make dits round dots and dahs clear strokes. A dot that looks like a short dash starts an argument.
- Do not worry about capitals: Morse has no upper or lower case.
- Leave out symbols Morse has no code for, such as # or emoji. Spell them as words.
How to write Morse code in text goes through the conventions in detail.
If you send by sound, say or hum the rhythm rather than reading out “dot, dash”. HI is di-di-di-dit, di-dit. A friend who learns letters as rhythms will soon read your knocks and hums without a chart, which makes the game faster and, for everyone else in the house, harder to follow.
Sending it as a sound
You can do all of this with a pencil. If you write your messages on a Mac, Dot & Dash turns them into Morse: type a message in Write and Send it, and the machine keys it with a tone while a paper tape prints on screen. For a secret, share it as an .m4a audio file. It holds the tone and the machine’s own sounds and no text, so your friend has to copy it by ear or with a chart. The file is named after the message, so rename it before you send it. Do not use the tape image or the video for a secret: the image prints each letter under its marks and the video shows the words as it prints, so both give the answer away. Keep those for messages meant to be read. Everything is made on your Mac and goes only where you send it. Scramble the text first if you want a cipher underneath. Write and audio need a license after the free 24 hours.
Questions
Can anyone read a message written in Morse code?
Yes. Morse is a public code with one standard table, so anyone with a chart, or anyone who knows Morse, can read it. It stays secret only from people who do not realize it is Morse or do not bother to look it up.
How do I make a Morse message harder to read?
Scramble the letters with a simple cipher first, such as shifting each letter one place along the alphabet, then put the scrambled text into Morse. The receiver needs both the Morse table and the shift you agreed.
How do you knock Morse code if every knock sounds the same?
Use two different sounds, a light fingertip tap for a dit and a firmer knuckle knock for a dah, and leave a clear pause between letters. Agree the rule with the other person before you start.
Is Morse code safe for private information?
No. It is fine for games and notes between friends, but anything private, such as a password or an address, needs real encryption, not Morse.