What is a Caesar Cipher?

The Caesar Cipher technique is probably the earliest encryption method which involves replacing each letter of a given text with a letter with some fixed number of positions down the alphabet. For example, a shift of “1” would replace A by B and B by C. This technique is named after Gaius Julius Caesar, who used it for secret communication with his officials.

Historically, each letter is shifted by an integer value – known as shift – of 3 but any number of shifts can be used. The ciphertext can then be decrypted by applying the same number of shifts in the opposite direction.    

The Caesar Cipher is not considered a strong method of encryption since it is easy to decode. Because of this, it is incorporated just as a part of complex encryption schemes. But even this basic level of encryption was certainly valuable, especially during Caesar’s campaigns of the 1^st century BC. The cipher meant that any messages intercepted by the enemy could not be easily read in plain text.

Algorithm for Caesar Cipher

1. Input: A combination of lower-case letters called “Text”. Any integer between 0-25 represents the cipher shift.
2. Procedure: Move each character – one at a time – by the required shift.

Depending on whether you’re encrypting or decrypting the text, traverse the character in a forward or opposite direction.

Advantages of a Caesar Cipher

The Caesar Cipher encryption technique was simple, but more useful than not having any form of encryption at all, especially for the times. Some main advantages of this early technique include:

• One of the simplest and easiest encryption methods that provide a layer of security to your data.
• Easy to memorize the cipher, so you can easily expand the cipher’s use due to easier end user experience and lower learning curve.
• Only have to use one type of key for the process.
• Needs limited computing resources. Messages can be quickly translated and responded to.
• For simple systems that cannot use complicated coding methods, the Caesar Cipher is best alternative.

Disadvantages of Caesar Cipher

• Too simple and easy to decrypt by an unauthorized user.
• Provides the minimum layer of security.
• The pattern of letters provides a clue to the hacker about the possible cipher shift.