What is the Caesar Cipher?
In this tutorial, we are going to see What is the Caesar Cipher?
This encoding system is one of the oldest since Julius Caesar would have used it. The coding principle is based on adding a constant value to all the characters of the message, or more exactly to their ASCII code.
It is just a question of shifting the set of values of the characters in the message by a certain number of positions, that is to say, in a way, of substituting each letter by another. For example, by shifting the message “HELLO” by 3 positions, we get “KHOOR”. When the addition of the value results in a letter exceeding the letter Z, it is easy to continue starting from A, which is equivalent to performing a modulo 26.
As an example of Caesar Cipher, in the movie Space Odyssey, the computer is called HAL. This nickname is in fact IBM shifted by 1 position downwards…
The key is the character corresponding to the value that is added to the message to perform the encryption. In our case, the key is C, because it is the 3rd letter of the alphabet.
This encryption system is certainly simple to implement, but it has the disadvantage of being totally symmetrical, which means that it is enough to make a subtraction to know the initial message. A primary method can consist of a simple subtraction of the numbers 1 to 26 to see if one of these numbers gives an understandable message.
A more advanced method consists in calculating the frequency of appearance of the letters in the coded message. Indeed, depending on the language, some letters appear more frequently than others (in French, for example, the most used letter is the letter E), so the letter appearing most often in a text encrypted by Caesar’s cipher will probably correspond to the letter E, a simple subtraction gives the encryption key…
Example of Caesar Cipher:
- What is S/MIME and How Does It Work?
- What is SET(Secure Electronic Transaction) Protocol?
- What is S-HTTP (Secure HTTP) Protocol?
- What is SSH Used For?
- What is SSL and How does it Work?
- What is PGP(Pretty Good Privacy) in Cryptography?
- What is RSA in Cryptography?
- What Is DES (Data Encryption Standard)?
- Vigenère Cipher with Example
- What is a Digital Certificate in Cryptography?
- What is a Digital Signature in Cryptography?
- What is Session Key in Cryptography?
- Asymmetric Encryption
- Symmetric Encryption
- What is Transposition Cipher With Example?
- What is ROT13 and How Does it Work?
- What is the Caesar Cipher?
- Substitution Cipher with Example
- What is Cryptography in Computer Network?
- Computer Security MCQs – Multiple Choice Questions and Answers – Part 1
- Computer Security MCQs – Multiple Choice Questions and Answers – Part 2
- Computer Security MCQs – Multiple Choice Questions and Answers – Part 3
- Computer Security MCQs – Multiple Choice Questions and Answers – Part 4
- Web Security And Transport Layer Security (TLS)
- IT Security & Data Protection: Similarities and Differences
