Kata

As a spy of your country you were able to acquire a secret letter sent from the general to the military camp near the war area. Your job is to recover the message using the key and the included cipher-text.The encryption used is a variation of the Caesar encryption system.

The arithmetic representation of Caesar cipher is : E_{n}(key)=(key+n)\mod {26} where 26 is the number of character in the alphabet and n the char to be encrypted.

The message that you Intercepted is divided into : The encryption key Key The message M

You don't know how the key is actually used, so you are required to figure out the encryption process and propose a decryption algorithm.

Hint: The messages sent are encrypted using the first 122 ASCII values instead of the 26 alphabet characters.

More details on Caesar cipher :https://en.wikipedia.org/wiki/Caesar_cipher