Caesar Cipher:
A great introduction to encryption, decryption, and code cracking, thanks to its simplicity it consider as one of the earliest encryption techniques is the Caesar Cipher.
YKIXKZ SKKZOTM GZ ZNK VGRGIK
The Caesar Cipher is a simple substitution cipher which replaces each original letter with a different letter in the alphabet by shifting the alphabet by a certain amount.
Decrypting:
As long as his message recipient know the shift amount, it is trivia to decode the message.
Cracking the cipher:
There are three main techniques he could use: frequency analysis, known plaintext, and brute force.
1.Frequency analysis:
Human languages tend to use some letters more than others. For example, “E” is the most popular letter in the English language. We can analyze the frequency of the characters in the message and identify the most likely “E” and narrow down the possible shift amounts based on that.
2.Known plaintext:
Another term for the original unencrypted message is plaintext. For example, messages tend to start with similar beginnings. In WWII, encrypted German messages always started with a weather forecast, which ultimately made them easier for British mathematician Alan Turing to crack.
3.Brute force
There are only 25 possible shifts (not 26 — why not?). The enemy could take some time to try out each of them and find one that yielded a sensible message. They wouldn’t even need to try the shifts on the entire message, just the first word or two.
Encryption, decryption, and cracking:
Thanks to this exploration of the Caesar Cipher, we now understand the three key aspects of data encryption:
-Encryption: scrambling the data according to a secret key (in this case, the alphabet shift).
-Decryption: recovering the original data from scrambled data by using the secret key.
-Code cracking: uncovering the original data without knowing the secret, by using a variety of clever techniques.
Resources:
Done by Omar-zoubi