Steganography means "hidden writing", where we send messages in hidden ways. Does this mean that something only experts can understand is called steganography?

  • 7
    Morse code is just an alternative representation. It doesn't hide anything.
    – Arminius
    Commented Nov 19, 2016 at 19:12
  • 12
    Morse code is not a kind of steganography but you could create a steganographic music that hides a morse code.
    – Zanon
    Commented Nov 19, 2016 at 23:47
  • 6
    "Does this mean that something only experts can understand is called steganography?". No. Steganography is writing a messages in such a way that nobody would guess that a hidden message exists in the first place. For example: you could cut your hair, engrave a message using a knife on the back of your head and wait a few months to let the hair grow again, then go to the recipient, cut your hair and show him your message. Who encounters you in transit wont suspect that you carry a hidden message on yourself.
    – Bakuriu
    Commented Nov 20, 2016 at 9:37
  • Invisible ink is another good example
    – Landric
    Commented Nov 21, 2016 at 11:36
  • 1
    Morse code rule #1: don't tell anyone about Morse code. Commented Nov 21, 2016 at 12:58

9 Answers 9


No. For it to be steganography, the message must be hidden in something (an image, a file, etc). When someone looks at that something, they should not be able to suspect that it contains a hidden message.

This isn't the case for morse code at all. There is no carrier that hides a message, there is just the message itself.

  • 5
    My favorite example of this was this story I hear about messengers who would have their head shaved, then a message written on their scalp. When the hair grows back, hidden message. Kind of time consuming, but a fun story.
    – Paul
    Commented Nov 20, 2016 at 13:09
  • @Paul Time consuming, and, I'm assuming, only one message can be sent per messenger, especially if the message is written in scar tissue.
    – jpaugh
    Commented Nov 21, 2016 at 3:26
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    Back in the time when traveling any meaningful distance took weeks or months, and cheap messengers were plentiful, it made a lot of sense.
    – vsz
    Commented Nov 21, 2016 at 5:24
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    So morse code hidden in a piece of music, for example, would be considered steganography?
    – Shawn
    Commented Nov 21, 2016 at 16:07
  • @Shawn yes, that's right. Then the music would be the carrier medium, and someone listening to it wouldn't suspect that it contains a hidden message (which isn't the case for morse code on its own; there someone very well may suspect that it contains a message and thus try to decode it).
    – tim
    Commented Nov 21, 2016 at 17:03

At some level, Steganography implies concealing a message within another. The root Greek word steganos means concealed within graphein writing.

The understanding of the message is not restricted to experts. Rather it is security by obscurity that only the target recepient(s) can read.

Morse code is just a way of representing information. It does not imply any secrecy, the reversal is well known.

However, you could hide messages by encoding it in Morse code and then placing it within a public message.

-- --- .-. ... . .. ... -. --- - ... - . --. .- -. ---

Examples: this excellent story about sending messages to hostages and this collection of Morse-encoded messages in pop music.

  • 20
    A captured US Navy Commander famously blinked the word torture in Morse Code at a televised press conference during the Vietnam War
    – Au101
    Commented Nov 19, 2016 at 16:46

Short answer: no. Encodings are not steganography.

Morse Code is the precursor to how modern day computers transmit information:

  • letters -> ascii values ('a' -> "97")
  • ascii values -> binary strings ("97" -> "0110 0001")
  • binary strings -> square waves of high and low voltage ("0110 0001" -> "_--____-")

There's nothing secretive here, we've just used a standardized system for turning text into something that's transmittable over a wire. That's called an encoding, there's no secrets.

Steganography, on the other hand is hiding information within another message so that even a trained observer is unlikely to notice that the hidden message even exists. Here's a toy example of hiding "Hi nsa" inside a seemingly unrelated message.

Hiding information's not so arduous.

You could certainly use Morse Code as part of steganography, like this example from wikipedia/steganography, but an encoding scheme by itself is not steganography:

Jeremiah Denton repeatedly blinked his eyes in Morse Code during the 1966 televised press conference that he was forced into as an American POW by his North Vietnamese captors, spelling out "T-O-R-T-U-R-E". This confirmed for the first time to the U.S. Military (naval intelligence) and Americans that the North Vietnamese were torturing American POWs.


Morse code is simply an encoding. Steganography means that the fact that a communication channel exists is hidden (hence, embedding in images, etc.)

The famous "blinking of messages" is steganography because the communication channel is hidden. The encoding used (i.e. morse code) is secondary.

Yes, the encoding method needs to be understood, but as soon as you realise that the message is using the Morse encoding, you can simply look up the decoding key and decode the message. Other encodings could be used.

There is another famous example when the US military used Navajo speakers to transmit sensitive data over the radio. While only another Navajo speaker could understand the communication (a relatively small set of people), it is very obvious that communication was occurring. This is also not steganography.


Morse code itself isn't steganography, but it's not incompatible with steganography. The key is that the Morse itself isn't the important message – there's something else hidden in there. For example, if we were sending Morse code between computers, then perhaps you could encode messages by adjusting the length of the dits and dahs by very small amounts, or by making small pitch changes if it were audible. The Morse message would remain identical, but it could be used to hide a very different message.

  • 1
    Alternately, you could use morse code as part of the scheme for encoding the hidden message, placing it somewhere in an image where that a random pattern is expected, such as in dithering.
    – Random832
    Commented Nov 20, 2016 at 0:00

The goal of steganography is to hide the fact that a message exists. If I hear a complex series of bips and beeps, then I'm going to guess that it's probably a message, and then I can start trying to figure out what it means.

But if you were to cleverly hide Morse code in the background music of a popular song, in a way that most people wouldn't even notice but Morse code experts would hear plain as day... that would be steganography.


If you hid the morse code, inside of an audio file, just at a higher/lower frequency or as breaks in the audio.....it would then be steganography.

Or if you modified an audio file, to show morse code in the spectrograph of the audio file, that would be steganography.


Money diluting before Havana that.

This is steganography using the morse code. Can you guess what's the hidden message?

Remove consonants and convert a,e -> SHORT, i,o,u -> LONG. You get
Money diluting before Havana that
O E / I U I / E O E / A A A / A
- - / - - - / . - . / . . . / .

However, the plain Morse code is what it is: a coding.

  • O E would make an N right, not an M? Commented Sep 5, 2019 at 6:31

You should distinguish between cryptography and steganography. Cryptography means that the content of the message is kept confidential, but the very fact of the message being sent is known to outsiders. Steganography goes even further to hide the mere fact of communication, possibly also using cryptography in the process.

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    While this isn't wrong, I'm not sure it answers the question since Morse code isn't cryptography either. Commented Nov 19, 2016 at 23:52
  • @Mike While this doesn't answer the question, Morse code is cryptography: it's encoding each letter with a different symbol. Granted, it's a one-to-one match and it's a published standard, so as cryptography goes it's next-to-useless, but it's still cryptography. Commented Nov 20, 2016 at 21:28
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    @AndrewLeach Ok, so you're arguing that the Morse encoding table is a secret key. I'll counter that historically this has always been publicly known, so you can't possibly hide anything with it. Commented Nov 20, 2016 at 21:40
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    @AndrewLeach how then do you differentiate between encoding and cryptography?
    – schroeder
    Commented Nov 21, 2016 at 7:50
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    @AndrewLeach Unless you're considering practices dating back to the napoleon wars, your definition of "cryptosystem" is simply incorrect. I suggest you have a quick look at Kerckhoffs's work.
    – Stephane
    Commented Nov 21, 2016 at 14:21

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