This week My main work is to find some examples of secret communication print through the research of historical radical press. Include: these methods can be used for a variety of purposes, such as to protect sensitive information, to convey hidden messages or codes, or to evade surveillance or censorship.
First, is the Morse code. This is the most common way to send secret messages in times of war.
For example, during the French Resistance in World War II, underground newspapers used cryptic messages and hidden meanings to convey information to resistance fighters and allies. Similarly, during the Civil Rights Movement in the United States, activists used coded language and symbols to communicate with one another and evade detection by authorities.
Then there are invisible inks, which are invisible after writing but can be made visible by heating or UV light. It was also used in secret communications during the two world wars. UV markers are now the most commonly used method of writing, with the written information being displayed when exposed to UV light.
The third example is Moiré pattern. This is a way of breaking up information that needs to be hidden into an unreadable pattern that needs to be read by means of a special card called Grating.
The last example is nvshu, a unique Chinese writing system that originated in China. It is a
script used exclusively by women and forbidden to men. The purpose is to serve as a secret communication method for female friends to communicate, and it is usually presented in the form of weaving and embroidery, so generally men will only regard this type of text as ordinary patterns.