Programming in C, you will implement Vigenere encryption and decryption with Cipher Block Chaining (CBC). \

The inputs to the encryption algorithm include Vigenere key, initial vector (IV) and plaintext and the inputs to the decryption algorithm include Vigenere key, IV and cyphertext

The encipher program will be run first. When encrypting, the encipher program will take inputs including plaintext, key and IV. The encipher encrypts the plaintext with the key & IV, and generate a file to store the ciphertext. Then when the decipher program is run, the ciphertext file will be used as input along with key & IV. The decipher program decrypts the ciphertext to recover the plaintext.

the encryption of Vigenere with CBC can be expressed as:

decryption of Vigenere with CBC as:

The outputs of the encipher program should include the following:

Key

IV(initial vector)

Block size

Plaintext (after preprocessing) printed on the screen

Number of characters in plaintext (before padding)

Ciphertext printed on the screen

Name of ciphertext file (ciphertext saved to a file)

Number of padding characters

The ciphertext file will be used as one of the inputs to the decipher. The outputs of the decipher program should include the following:

Ciphertext file name

Number of characters in ciphertext

Recovered plaintext printed on the screen

Co = E (Po + IV) = (Po + IV + keyword) mod 26 Gj = E (P, + Cj-1)-(P, + Cj-1-keyword) mod 26