8-9! 20-8-9-19 9-19 1 19-21-2-19-20-9-20-21-20-9-15-14 3-9-16-8-5-18.
(Translation: Hi! This is a substitution cipher.)

A substitution cipher is where a set of symbols is swapped for another set of characters. In the example in the image, I swapped the English alphabet for its corresponding numerical values (A = 1 and so on). This article will focus on how you can make your own cipher.

The most notable examples of substitution ciphers include A1B2Z26, morse code, and pig pen. A1B2Z26 is where letters are swapped out for their numerical counterparts as I used at the beginning of the article. Morse code is a versatile cipher comprising short and long sounds, symbols, or light flashes. It was initially used to send telegraph messages but can be applied to many other mediums. In text, a word like “cats” is written like this: -.-. .- – … . A pig pen is a cipher where letters are swapped for symbols. There are many other ciphers in this vein, but the pig pen is one of the more famous. There are also ciphers where letters are swapped out for different letters, but they tend to have many layers—for example, the caesar cipher and the vigenére cipher.
To make your substitution cipher, you need minimal supplies. You can use a phone, computer, or pen and paper to create one. I recommend having the English alphabet written/typed on whatever medium you’re using.

Where you go from there is up to you. While substitution ciphers are simple in encrypting messages, they can range from looking like a language from another world to a page of complete gibberish.

Examples:

It’s amusing to encrypt and decrypt messages, or even give ciphers to friends and family to decode.

Cryptology, the study of codes and ciphers, is fascinating. Substitution ciphers are the tip of a giant iceberg. I recommend looking at vigenére ciphers and steganography if you’re just as interested in this coding language as I am.