problems.txt

Change the base code for ciph1.c and deciph1.c to implement the following on text files with 
- all english uppercase and lowercase letters,
- numerics,
- and printable charaters including '`', '`', '\b', '\t', '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '-', '_', '+', '=', ',', '.', 
  '?', '/', '\', ',' '{', '[','}',']',':', ';', '"', ''', '<', '>', '?'.

1. Implement a Caesar cipher on a text file including all english alphabets (upercase and lowercase), and numbers. ASCII values or any other indexing can be used. 
The K value would take a random sequence of values 11,7,13,3,11,17,3,19,5 after each character in a rotating version. Implement the deciphering. Also, write a 
brute-force code to break the ciphertext where the attacker knows the ciphertext, the fact that K values are prime numbers between 3 and 19, and they change randomly after each character with a periodicity of 10. 
calculate the time to generate all possible plaintexts using brute force.

2. Implement a playfair cipher and decipher with 10X10 matrix with the key "A quick brown fox LEAPS OVER a BLUE Well". Write a possible algorithm and the code 
(if possible) to break the ciphertext with the knowledge of the length of cipherkey.

3. Implement Hill cipher and decipher modules with a 8X8 square matrix. The matrix elements should be set according to a random number sequence between 11 and 197
without repetition. Write an algorithm and the code (if possible) to break the ciphertext with the knowledge that the matrix is 8X8 and the value range is between 1
to 250.

4. Implement affine cipher and decipher modules where modulo = 128, C = (C + 4)mod 128 after each character and A changes to the next bigger prime number starting
from 113 after every 20 characters.

5. Implement the Vignere cipher and decipher with the same key as problem number 2.

6. Implement a three-stage rotor machine cipher where the mapping are generated through 3 different sets of non-repeating random numbers between 30 - 127.