This is for python.

(Question 3, will post others separately.)

# 3. Implement sub_decrypt(password) def sub_decrypt(password, ciphertext): """Decrypt ciphertext using the substitution cipher. If a character is not in the key, the character remains unchanged. The ciphertext should be normalized to all lowercase letters. s = 'le tge svhpbkeges. cyee ti bape.' sub_decrypt(s) # --> we are discovered. flee at once. :param password: the password used to generate a key :type password: str :param ciphertext: the text to be decrypted :type ciphertext: str :return: the plain text that results from decrypting the ciphertext :rtype: str """ # implement this function! return '' def vig_encrypt(key, message): """Encrypt a message using the vigenre cipher. Punctuation is preserved. :param key: the key used for encrypting the message :type key: str :param message: the message to be encrypted :type message: str :return: the ciphertext, as a string, produced by encrypting the message :rtype: str """ cypher_text = '' alphabet = gen_consecutive_chars() key_len, alphabet_len = len(key), len(alphabet) # or replace next two lines with... # for i, ch in enumerate(message): for i in range(len(message)): ch = message[i] # based on key... what row (labeled by letters) in table will we # use? the example in the book shows a mapping of the key to a # message: # DAVINCIDAVINCIDAVINC # the eagle has landed # consequently, the row in we use for the first letter, t is D # (row_letter is D for first letter, t) row_letter = key[i % key_len].lower() # calculate offset to simulate shifting letters for each row: # again, using the first letter t, and D as the row letter... # D is at position 3 of the alphabet, which means that the key # (the alphabet) is shifted by 3: defghijklmnopqrstuvwxyzabcd # ... let's save this shift in a variable called offset offset = alphabet.index(row_letter.lower()) try: # so now, we can translate our original character, ch, by # finding out where it is in the offset row represented by D. # simply add the offset to what ch's position would be in the # alphabet (so if ch is t and the key specifies that the # offset is 3, then the index of the character that t is # translated to 19 + 3)... other_index = (alphabet.index(ch) + offset) % alphabet_len # if working with the letter and key mentioned above, t is # translated to the letter at index 22 of the alphabet: w cypher_text += alphabet[other_index] except ValueError: cypher_text += ch return cypher_text

I don't understand how to implement this (or the others I posted seperately) function, can I get some kind of walkthrough on these? (Code + comments explaining how or why it's like that would be awesome.)