Cryptography is the art of protecting information by transforming it (encrypting it) into an
unreadable format, called cipher text. The cipher text can be decrypted (deciphered) into plain
text by the use of a secret key.
Referencing the above information, how can you get started on writing a XOR cipher program using the C programming language? The program must accept as input from the user a value between 0 and 255 to be used as the secret key, the name of the input file and the name of the output file. No line in the input file should contain more than 4096 characters.
After the user would have provided their secret key, the program should read and perform an
XOR cipher on the contents of the input file and write the result to the output file.
If the input file has already been encrypted and the identical secret key that was used to
perform the initial encryption is provided, then the contents of the output file should be
deciphered into its original plain text.