Suppose you want to send a secret message to your friend.
Since you don’t want anyone else to read the message, you and your friend decide on a code. For example, A is 1, B is 2. You decide that space should be indicated by a semi-colon, and a comma separates two letters.
So, “Come Home” becomes 3,15,13,5;8,15,13,5.
Once the message has been converted from English to numbers, we say it is ‘encrypted‘. When your friend decodes the message to read it, it has been ‘decrypted‘. A message that is not in any code is unencrypted.
Encryption in Computing
When we send emails or messages to someone, an encrypted message, even if it is intercepted or hacked, will not be of any use to the hacker. They will just get a code.
Slowly, solutions started coming that do this encryption and decryption automatically. This meant that we could create tougher codes which could only be decoded using other computers.
The first people to use encryption at large scale were, not surprisingly, armies. In the second world war, the Germans were invincible because of their encryption machine called Enigma. The British mathematician, Alan Turing, worked tirelessly to create a machine that could decode Enigma. As soon as he succeeded, German messages were intercepted and the Allies won the war.
Today, encryption is used in most computer applications. Starting with financial and other sensitive information, encryption has moved to almost all internet based communication.
Even messaging platforms like Whatsapp, Signal, and Telegram offer users end to end encryption. This means that even their own employees cannot read what is being written in the messages between two people.