Produce a program which will read unencrypted ‘plaintext’ text from a file and encode it with a numerical shift between 1 and 26 e.g 2. It should write the encoded ‘ciphertext’ to a new file.
More information can be found on the shift cipher at Wikipedia.
Variable and Validation Table
|Variable Name||Data Type||What it does?||Origin||Validation Req.|
|shift||Integer||Used to move each letter along the alphabet e.g. 2 would mean a = c.||User Input||Must be a positive integer between 0 and 26|
|message||String||This is the text that the user wants encrypted.||User Input||Must be an alpha numeric string of length greater than 0.|
|ciphertext||String||Stores the encoded message||Process||N/A|
- Write a decryption function for the Shift Cipher.
- Write a Function called Atbash which encodes the file using AtBash e.g. A ?Z, B ?Y, C ?X etc.
- Write a code breaking function for the Shift Cipher.