What clever non-classified forms of communications have you either used or known about?

SPC David S. — Fri, 03 Sep 2021 15:40:46 -0400

I recently wrote a program that uses open source methods to encrypt a message and then hides the message within a digital image. It first uses a Vigenere cipher to encrypt the message and then hides the message within the RGB values of the pixels by modifying the least significant bit of each byte. For example the letter A equals 01000001 in binary form. I can hide this by editing the least significant value of the RGB binary values to match the binary values for the letter A. For example a pixel has a binary value of 11111111 which is red. If I change the last bit 1 to 0, the least significant bit, the result would be 11111110. This produces almost an identical color impossible to detect with the human eye. In this example a solid field of red pixels would be modified to 1 [login to see] [login to see] 0 1 [login to see] [login to see] 0 1 [login to see] 1111 to hide the letter A. The message can then be resolved by reversing the process. This technique is called steganography. As you can see the images look identical yet one contains a secret message. Now imagine a 1TB thumb drive full of pictures. You go from a spy caught with thousands of state secret documents to a tourists with lots and lots of pictures of mother Russia.

As such what clever ways have you used or know about that can hide information in plain sight.

https://www.computerhope.com/jargon/l/leastsb.htm
https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher

What is LSB (Least Significant Bit)?

Computer dictionary definition of what LSB (least significant bit) means, including related links, information, and terms.

Response by MSG Private RallyPoint Member made Sep 3 at 2021 4:17 PM

MSG Private RallyPoint Member — Fri, 03 Sep 2021 16:17:43 -0400

Pig Latin

Response by CWO4 Terrence Clark made Sep 3 at 2021 5:02 PM

CWO4 Terrence Clark — Fri, 03 Sep 2021 17:02:26 -0400

Kudos to you SPC David S. ! Beats the hell out the system I've been using where the letter A is an apple emoji, B is a bicycle emoji and the number 1 is a thumbs up emoji.
Seriously, that's impressive. How small is the hardware to code and decode?

Response by SFC Casey O'Mally made Sep 3 at 2021 9:12 PM

SFC Casey O'Mally — Fri, 03 Sep 2021 21:12:25 -0400

The closest I ever got was a made up just for fun code our Company RTOs created for calling for (Company) fire (i.e. 60mm mortars). We would order Chicken McNuggets (call for fire) and then the dipping sauce was what type: Hot Mustard was White Phosphorous, Sweet and Sour was Lum, and BBQ was HE. (You, this is me. We're Hungry. I need nuggets delivered to my position, side of BBQ.)