Humanity has explored ways to keep secrets since the early days — non-standard hieroglyphs were found in a tomb from the Old Kingdom of Egypt around 1900 BC. Julius Caesar invented a substitution cipher in 60 BC. The Enigma machine was designed in 1918 to protect communications in the banking industry. In the early 1970s, IBM founded the "crypto group," which developed a block cipher to protect its customers' data. In 1973, the US adopted it as a national standard; it took 25 years for hackers to crack it.

This project allows you to write a program for encrypting messages and files. But first, you need some basic knowledge about ciphers. You will start with the validation of user input. Then you need to convert chars to ASCII values. In the end, you will build a simple cipher that creates a file and encrypts it with a Linux utility.