Question

What more powerful 1 Introduction to Iteration As you wstring the bread and better of Pythopo is that they function a s to list for instance the >>> for item in product A","product","product c printite) "product A" o de): "productD Would you agree with this? Now, what happens to a street look at an emple >>> for item is "ABCD: print(item) In Python tige ww w strings ends up printing each individual character. Now, how s the ong wewed in a cor? 1.1 Introduction to ASCII ASCILA Standard Code forma text. Thus, we be l i ebt, For a what we this table is by fetching the corresponding decal value for a which is 1000001 in base 2 Thankfully, the ord function in Pythm Sch and S ong with representa were the ASCII table How you t A tos e d with a cu >>> ord("A") To the proces s the chef >>> chr(65) 1.2 Applications in Encryption Imagine you have a very importa ge that you wish to cal O p po up with is to loop we cach character is your Sitchis ASCII del ac t to this decimal that only you and your trusted know that we took -modified decimal them buck to the there w a s to visualize this modification is in the As you can we have to an a pewa tech the crepeling ASCII integer. We the modified, o bited the with a ver low to treated partia e o 2 in By decoding this mod hack to be charter wed with modified, and Evere. W y o the lege wbove, but rather that add 2.o tract from the ASCII . The r e you decrypto important to its original Te ASCII ord10101101116 1162112 SUN +2 111 103 103 118 319 115 31 5 11 11 Table 1. Shifting ASC code to vie w Caesar Cipher, made f or by the Roman Empire, Jules C th i s is folk 1.3 Problem You are given the string The quick brown fox jumps over the lay dog with this string, implement the Caesar per disease in Section 1 Siddharacters - what you crypted string Next, implement logic that takes this encrypted stri p eoduces the For consideration of full points, provide alle code,

Answer 1

Thanks for the question.

Here is the completed code for this problem. 

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# returns the list of letters that we want to encrypt or decrypt
def createAlphabet():
    alphabets='abcdefghijklmnopqrstuvwxyz'
    alphabets+='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    alphabets+=' '
    alphabets+=',.-~#'

    return alphabets

#function takes in the plain text and the key
# function returns the encrypted text back
def encryptCeasarCipher(plaintext,key):
    alphabets = createAlphabet()

    encrypted_text=''
    for letter in plaintext:
        if letter in alphabets:
            index = alphabets.index(letter)
            forward_index = (index+key)%len(alphabets)
            encrypted_text+=alphabets[forward_index]
        else:
            encrypted_text+=letter
    return encrypted_text

# function takes in the encrypted text and the key
# function returns the decrypted text back
def decryptCeaserCipher(plaintext,key):
    alphabets = createAlphabet()
    decrypted_text=''
    for letter in plaintext:
        if letter in alphabets:
            index = alphabets.index(letter)
            backward_index = index-key%len(alphabets)
            decrypted_text+=alphabets[backward_index]
        else:
            decrypted_text+=letter
    return decrypted_text

# function ask user to enter the plain text and the key that needs to be used
# function first prints the encrypted text and again using the encrypted text and the same
# key decrypts an prints the original text again
def main():
    plaintext = input('Enter a message: ')
    key = int(input('Enter key : '))
    encrypted_message = encryptCeasarCipher(plaintext,key)
    print('Encrypted Message: ',encrypted_message)
    decrypted_message = decryptCeaserCipher(encrypted_message,key)
    print('Decrypted Message: ',decrypted_message)

main()

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# returns the list of letters that we vant to encrypt or decrypt def createAlphabet (): alphabets='abcdefghijklmnopqrstuvwxy z' 3 alphabets+='ABCDEFGHIJKLMNOPORSTUVWXYZ' alphabets+=' alphabets+= -~#' return alphabets E#function takes in the plain text and the key 10 A# function returns the encrypted text back def encryptCeasarCipher (plaintext, key) : 11 12 alphabets createAlphabet () 13 14 encrypted_text='" for letter in plaintext: if letter in alphabets: 15 16 17 index = alphabets.index (letter) 18 forward index (index+key) $len (alphabets) 19 encrypted_text+=alphabets [forward_index] else: 21 22 encrypted_text+=letter return encrypted_text 23 24 E# function takes in the encrypted text and the key A# function returns the decrypted text back 25 26 def decryptCeaserCipher (plaintext, key) : A 27 alphabets = createAlphabet () 28 decrypted text='' for letter in plaintext: if letter in alphabets: 29 30 31 alphabets.index (letter) index = 32 backward_index = index-key$len (alphabets) 33 2 Terminal Python Console 4: Run 6: TODO IDE and Plugin Updates: PyCharm is ready to update. (8 minutes ago) * 2: Favorites . 2: Structure I 1: Proje

for letter in plaintext: 30 if letter in alphabets: 31 alphabets.index (letter) index = 32 backward_index index-key%len (alphabets) 33 decrypted_text+=alphabets [backward_index] 34 else: 35 decrypted_text+=letter 36 return decrypted_text 37 38 E# function ask user to enter the plain text and the key that needs to be used # function first prints the encrypted text and again using the encrypted text and the same A# key decrypts an prints the original text again E def main () : plaintext = input ('Enter a message: ') key = int (input ('Enter key : ')) 39 40 41 42 43 44 encrypted_message = encryptCeasarCipher (plaintext, key) 45 print ('Encrypted Message: ',encrypted_message) decrypted_message decryptCeaserCipher (encrypted_message, key) 47 print ('Decrypted Message: ',decrypted_message) 48 49 main () 50 Run: C:\Users\User\PycharmProjects\Analytics\venv\Scripts\python.exe C:/Users/User/PycharmProjects/Analytics/ .py Enter a message: The quick brown fox jumps over the lazy dog. Enter key: 2 Encrypted Message: Vjg. swkem.dtgyp.hqz.lworu.qxgt.vjg.ncBA.fqi- Decrypted Message: The quick brown fox jumps over the lazy dog. Process finished with exit code 0 >> 4: Run 6: TODO Python Console Terminal IDE and Plugin Updates: PyCharm is ready to update. (9 minutes ago) * 2: Favorites . Z: Structure 1: P