Caesar cipher in the terminal

Caesar cipher:

In cryptography, a Caesar cipher, also known as Caesar’s cipher, the shift cipher, Caesar’s code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. The method is named after Julius Caesar, who used it in his private correspondence.

You can easily use it in the terminal with the help of tr.

Obfuscate Hello World:

$ echo "Hello World" | tr A-Za-z W-ZA-Vw-za-v
Dahhk Sknhz

And undo it by flipping the arguments of tr:

$ echo "Dahhk Sknhz" | tr W-ZA-Vw-za-v A-Za-z
Hello World

If you also want to obfuscate capitalization, you need to mix it a bit more:

$ echo "Hello World" | tr A-Za-z w-zA-Ma-vN-Z
DnuuO fORum

Of course this is not a cryptographically secure encryption but it is a nice gimmick to obfuscate the content of texts.

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Did you know that you can use echo "Hello World" | rev to obfuscate text in your terminal?