You can write an Invisible Secret Text Message in an Image File, by following this trick laid down in this post. All you need is the Notepad!

Can they crack your code if they “intercept” your message? Extra: What if the person who intercepts your message knows about Caesar ciphers? Does that make it easier to crack the code?

Would it be possible to interpret a message and a language not only from a different species, but from entities from another planet?

This “extraterrestrial message” was created by artists and scientists for a project called A Sign in Space, which challenges people around the world to interpret an imagined alien signal.

Dozens of people answered an astrophysicist’s call to decrypt a transmission from an imaginary civilization 50 light-years away.