Abstract:Cryptographic methods are used worldwide to keep
information safe. Monoalphabetic, Polyalphabetic or Polygraphic
substitutions, etc., are methods that can make the information
secure. Once encrypted, the receiver should be able to understand
the message with a given key. If there is no key, the formula
called Index of Coincidence (IC) can help deciphering. It narrows
down the search for the method used with the result obtained
from the IC formula. Using the MATLAB IDE, we will implement
the ciphers mentioned above and along with the IC formula,
determine the cipher if no key is present. |