- The Caesar cipher program implemented is capable of encryption and decryption of lowercase and uppercase alphabets, rest all characters in the input string are left as they were originally.
- An integer key is to be provided which indicates the offset from plaintext alphabet to ciphertext alphabet.
- The code for Caesar cipher has two library files - caesar.c and caesar.h, for implementing the basic routines of encryption, decryption and brute force decryption using the semantics of Caesar cipher.
- Two seperate programs for encrypting and decrypting - encrypt.c and decrypt.c are implemented, for user access, wherein both of these programs utilise the library files discussed above.
- Both the programs take the key as a command line argument. Also the encryption program takes the plaintext to be encrypted from the standard input and prints the encrypted ciphertext to the standard output. And the decryption program takes the ciphertext to be decrypted from the standard input and prints the decrypted plaintext to the standard output.
- The Monoalphabetic cipher program implemented is capable of encryption and decryption of lowercase and uppercase alphabets, rest all characters in the input string are left as they were originally.
- An integer key table of 26 elements, where each number is (mod 26) and no element is repeated is to be provided to the program, which indicates the mapping from the plaintext character number to the ciphertext character number.
- The code for Monoalphabetic cipher has two library files - monoalpha.c and monoalpha.h, for implementing the basic routines of encryption, decryption and brute force decryption using the semantics of Monoalphabetic cipher.
- Two seperate programs for encrypting and decrypting - encrypt.c and decrypt.c are implemented, for user access, wherein both of these programs utilise the library files discussed above.
- Both the programs take the key table as a command line argument. Also the encryption program takes the plaintext to be encrypted from the standard input and prints the encrypted ciphertext to the standard output. And the decryption program takes the ciphertext to be decrypted from the standard input and prints the decrypted plaintext to the standard output.
- If the input key table is invalid, then the output string is empty.
