We Keep Coding

Encoding a password with special characters

I am in an into to Programming class and the assignment is in part to shift the letters of a valid password by +1 if it is a letter or number and -1 if it is a !##$ special character. I have most of it working with my below code but I always get the wrong output for the special characters. If I use to the code of anything high like 128 then I get the wrong symbol.
I am using the code from an encryption program from the other week and slowly changing things but I feel like this is too involved for something simple
If I enter the password UMA#augusta2020 I need to get the output VNB?bvhvtub3131 but I either end up with a space, b, or wrong symbol when I change the code input between 26,64,96,128, etc.
I have updated the code to fix small errors
def main():
print("This program validates and encrypts a password")
print()
main()
# The Encryption Function
def cipher_encrypt(plain_text):
encrypted = ""
for c in plain_text:
if c.isupper(): #check if it's an uppercase character
c_index = ord(c) - ord('A')
# shift the current character by key positions
c_shifted = (c_index + 1) % 26 + ord('A')
c_new = chr(c_shifted)
encrypted += c_new
elif c.islower(): #check if its a lowecase character
c_index = ord(c) - ord('a')
c_shifted = (c_index + 1) % 26 + ord('a')
c_new = chr(c_shifted)
encrypted += c_new
elif c.isdigit():
# if it's a number,shift its value
c_new = (int(c) + 1) % 10
encrypted += str(c_new)
else:
# if its neither alphabetical nor a number, -1
c_shifted = (c_index - 1) % 128 + ord('a')
c_new = chr(c_shifted)
encrypted += c_new
return encrypted
plain_text =input("Enter your Password: ")
print()
ciphertext = cipher_encrypt(plain_text)
print()
print("Your Password: ", plain_text)
print()
print("Your password is valid and encrypted it is: ", ciphertext)
print()

Here is a much cleaner approach:
def cipher_encrypt(plain_text):
alpha = 'abcdefghijklmnopqrstuvwxyz'
digits = '0123456789'
puncs = '!"#$%&\'()*+,-./:;<=>?#[\\]^_`{|}~'
encrypted_text = ''
for c in plain_text:
if c.lower() in alpha:
c_index = alpha.index(c.lower())
e_index = (c_index + 1)%len(alpha)
if c == c.lower():
encrypted_text += alpha[e_index]
else:
encrypted_text += alpha[e_index].upper()
elif c in digits:
c_index = digits.index(c)
e_index = (c_index + 1)%len(digits)
encrypted_text += digits[e_index]
else:
c_index = puncs.index(c)
e_index = (c_index +len(puncs) - 1)%len(puncs)
encrypted_text += puncs[e_index]
return encrypted_text
In this approach I deal with each caharcter in plain text by:
Determining idf the char is part of alpha by making use of the c.lower() function to isolate alpha chars and then find an index modulo the len of alpha. Then I determine if I need an uppercase char or lower case in the encrypted text.
I use the same modulo approach for digits, but don't have to worry about upper and lower, finally
I find the index for the punctuations found in the plain_text

How to leave punctuation unchanged in Caesar Cipher? - Python

I'm having trouble trying to leave the punctuation unchanged while encrypting or decrypting a message
# encryption
message = input("Enter a message to be encrypted: ") # user inputs message to be encrypted
offset = int(input ("Enter an offset: ")) # user inputs offset
print ("\t")
encrypt = " "
for char in message:
if char == " ":
encrypt = encrypt + char
elif char.isupper():
encrypt = encrypt + chr((ord(char) + offset - 65) % 26 + 65) # for uppercase Z
else:
encrypt = encrypt + chr((ord(char) + offset - 97) % 26 + 97) # for lowercase z
print ("Your original message:",message)
print ("Your encrypted message:",encrypt)
print ("\t")
An example of what the output looks like if I try to encrypt a message with punctuation (offset of 8):
Your original message: Mr. and Mrs. Dursley, of number four Privet Drive, were proud to say that they were perfectly normal, thank you very much.
Your encrypted message: Uzj ivl Uzaj Lczatmgh wn vcujmz nwcz Xzqdmb Lzqdmh emzm xzwcl bw aig bpib bpmg emzm xmznmkbtg vwzuith bpivs gwc dmzg uckp
I suspect this program is changing the punctuation to letters due to the
chr(ord(char)) function.
Is there any way I can add in the actual punctuation to the encrypted message without changing the code too much? I would really appreciate any help, thank you!

You can get your desired result with just a one liner change by handling all non alpha characters in the first conditional using isalpha()
# encryption
message = input("Enter a message to be encrypted: ") # user inputs message to be encrypted
offset = int(input ("Enter an offset: ")) # user inputs offset
print ("\t")
encrypt = " "
for char in message:
if not char.isalpha(): #changed
encrypt = encrypt + char
elif char.isupper():
encrypt = encrypt + chr((ord(char) + offset - 65) % 26 + 65) # for uppercase Z
else:
encrypt = encrypt + chr((ord(char) + offset - 97) % 26 + 97) # for lowercase z
print ("Your original message:",message)
print ("Your encrypted message:",encrypt)
print ("\t")

Same as you do it with a space, you can do it with any character.
if char in string.punctuation+' ':
encrypt = encrypt + char

Interactive rot13 cipher

I have a code and I'm having trouble making it interactive.
Here's the problem:
"""Write a function called rot13 that uses the Caesar cipher to encrypt a message. The Caesar cipher works like a substitution cipher but each character is replaced by the character 13 characters to “its right” in the alphabet. So for example the letter “a” becomes the letter “n”. If a letter is past the middle of the alphabet then the counting wraps around to the letter “a” again, so “n” becomes “a”, “o” becomes “b” and so on. Hint: Whenever you talk about things wrapping around its a good idea to think of modulo arithmetic (using the remainder operator)."""
Here's the code to this problem:
def rot13(mess):
alphabet = 'abcdefghijklmnopqrstuvwxyz'
encrypted = ''
for char in mess:
if char == ' ':
encrypted = encrypted + ' '
else:
rotated_index = alphabet.index(char) + 13
if rotated_index < 26:
encrypted = encrypted + alphabet[rotated_index]
else:
encrypted = encrypted + alphabet[rotated_index % 26]
return encrypted
def main():
print(rot13('abcde'))
print(rot13('nopqr'))
print(rot13(rot13('since rot thirteen is symmetric you should see this message')))
if __name__ == "__main__":
main()
I want to make it interactive where you can input any message and you can rotate the letters however many times as you want. Here is my attempt. I understand you'd need two parameters to pass, but I'm clueless as to how to replace a few items.
Here's my attempt:
def rot13(mess, char):
alphabet = 'abcdefghijklmnopqrstuvwxyz'
encrypted = ''
for char in mess:
if char == ' ':
encrypted = encrypted + ' '
else:
rotated_index = alphabet.index(char) + mess
if rotated_index < 26:
encrypted = encrypted + alphabet[rotated_index]
else:
encrypted = encrypted + alphabet[rotated_index % 26]
return encrypted
def main():
messy_shit = input("Rotate by: ")
the_message = input("Type a message")
print(rot13(the_message, messy_shit))
if __name__ == "__main__":
main()
I don't know where my input should be taking place in the function. I have a feeling it could be encrypted?

This is probably what you're looking for. It rotates the message by the messy_shit input.
def rot13(mess, rotate_by):
alphabet = 'abcdefghijklmnopqrstuvwxyz'
encrypted = ''
for char in mess:
if char == ' ':
encrypted = encrypted + ' '
else:
rotated_index = alphabet.index(char) + int(rotate_by)
if rotated_index < 26:
encrypted = encrypted + alphabet[rotated_index]
else:
encrypted = encrypted + alphabet[rotated_index % 26]
return encrypted
def main():
messy_shit = input("Rotate by: ")
the_message = input("Type a message")
print(rot13(the_message, messy_shit))

def rot(message, rotate_by):
'''
Creates a string as the result of rotating the given string
by the given number of characters to rotate by
Args:
message: a string to be rotated by rotate_by characters
rotate_by: a non-negative integer that represents the number
of characters to rotate message by
Returns:
A string representing the given string (message) rotated by
(rotate_by) characters. For example:
rot('hello', 13) returns 'uryyb'
'''
assert isinstance(rotate_by, int) == True
assert (rotate_by >= 0) == True
alphabet = 'abcdefghijklmnopqrstuvwxyz'
rotated_message = []
for char in message:
if char == ' ':
rotated_message.append(char)
else:
rotated_index = alphabet.index(char) + rotate_by
if rotated_index < 26:
rotated_message.append(alphabet[rotated_index])
else:
rotated_message.append(alphabet[rotated_index % 26])
return ''.join(rotated_message)
if __name__ == '__main__':
while True:
# Get user input necessary for executing the rot function
message = input("Enter message here: ")
rotate_by = input("Enter your rotation number: ")
# Ensure the user's input is valid
if not rotate_by.isdigit():
print("Invalid! Expected a non-negative integer to rotate by")
continue
rotated_message = rot(message, int(rotate_by))
print("rot-ified message:", rotated_message)
# Allow the user to decide if they want to continue
run_again = input("Continue? [y/n]: ").lower()
while run_again != 'y' and run_again != 'n':
print("Invalid! Expected 'y' or 'n'")
run_again = input("Continue? [y/n]: ")
if run_again == 'n':
break
Note: It's more efficient to create a list of characters then join them to produce a string instead of using string = string + char. See Method 6 here and the Python docs here. Also, be aware that our rot function only works for lowercase letters of the alphabet. It'll break if you try to rot a message with uppercase characters or any character that isn't in alphabet.

Python code hangs after entering all inputs

Hi guys Here is my error:
Phrase to be Decrypted: n
Shift keyword, Word only: ]YY
The code will write the Decryption to a file of your choice
Please input the number to decrypt by: 44
*hang*
Inputs:
Phrase: n
Keyword: ]YY
Decryption shift: 44
What it should do is decrypt the Phrase into Chicken and the keyword into Egg. The number I have input is the shift that the code performs to scramble the keyword.
Here is my code:
import getpass
import random #imports random module
import codecs #imports codecs module for encode task (UTF8)
import time
w = getpass.getpass("Input the Password: ")
with open('Password.txt') as f:
found = False
for line in f:
if w in line:
import random
import codecs
phrase = input('Phrase to be Decrypted: ') #Asks user to input a phrase
shift_key = input("Shift keyword, Word only: ") #Asks user to input a keyword
print ("The code will write the Decryption to a file of your choice")
Encryption_Base = ["abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890,./;:<>?'##~]}[{=+-_)(*&^%$£!`¬\|"] #Encryption base. Randint uses this.
key_encryption = int(input("Please input the number to decrypt by: ")) #Grabs a random number between 0 and 94
Cipher = '' #Cipher is blank, to be used later.
for c in shift_key: #Looks for a letter in the keyword, in this case c
if c in Encryption_Base: #Looks for the same letter in the string.
Cipher -= Encryption_Base(Encryption_Base.index(c)-(key_encryption)/(len(Encryption_Base))) #Turns the keyword into a different letter
def Keyword_Encryption(key, phrase): #Defines the new variable
if len(phrase) < len(key): #If the phrase is longer than the key
while len(phrase) < len(key): #While the phrase is longer than the key
length_to_add = len(phrase) + len(key) #Shorten the key to the length of the phrase
key = key + key[0:length_to_add]
elif len(phrase) > len(key): #However if the phrase is shorter than the key
while len(phrase) > len(key):
length_to_sub = len(key) + (len(key) + len(phrase)) #Make both of them equal.
key = key[0:length_to_sub]
else:
pass #Anything else stops the code.
shifted_phrase = '' #Shifted phrase is blank for later
for i in range(len(phrase)): #Find a letter in the length of the phrase
new_letter = (ord(key[i]) + 50) - (ord(phrase[i]) + 50) - 50 #Change the order of the key
if new_letter < 1220: #If the new letter is higher than 1220
new_letter = chr(new_letter + 26) #Create an extra character
else:
new_letter = chr(new_letter) #Anything else creates a new character (could be overflow?)
shifted_phrase = shifted_phrase - new_letter #Adds the new letter onto the encrypted phrase
return shifted_phrase
result = Keyword_Encryption(Cipher, phrase) #Adds the Cipher and phrase to keyword encryption so that the user knows what key to use to decrypt it.
print (" ")
print (":-) " * 3 + "Encrypting Phrase... " + ":-) " * 3) #All of ths makes it look pretty
print (":-) " * 3 + "Done! " + ":-) " * 3) #
print (" ") #
print ('Here is your Encrypted Phrase:' + (result) + (Cipher) + (str(key_encryption))) #Finally prints the result
time.sleep(2)
FileName = input("Enter a filename for the encrypted phrase and key to be written to: ") + ".txt"
file = codecs.open(FileName, "w", encoding = "utf8") #Opens the file Encrypted.txt and encodes it in UTF to support unicode.
file.write (str(result) + " " + (Cipher) + " " + (str(key_encryption))) #Writes the phrase and key seperately to aid the user
file.close() #Closes the file
k=input("Prompt: ")
if not found:
print("Access Denied")
time.sleep(5)
Any help would be greatly appreciated :)
EDIT:
New error:
Phrase to be Decrypted: n
Shift keyword, Word only: ]YY
The code will write the Decryption to a file of your choice
Please input the number to decrypt by: 44
Traceback (most recent call last):
File "E:\Python\Password Encryption\Decryption.py", line 56, in <module>
result = Keyword_Encryption(Cipher, phrase) #Adds the Cipher and phrase to keyword encryption so that the user knows what key to use to decrypt it.
File "E:\Python\Password Encryption\Decryption.py", line 46, in Keyword_Encryption
new_letter = (ord(key[i]) + 50) - (ord(phrase[i]) + 50) - 50 #Change the order of the key
IndexError: string index out of range

Brute force decryption python

Hello I am trying to brute force decrypt a word 58 times but my code keeps adding more characters for every loop it does. Has anyone got any idea what I am doing wrong I just learnt python 3
Here is my attempt to decrypt
word = input("Please enter the encrypted word: ")
message = ""
times = 0
for i in range(58):
for ch in word:
val=ord(ch)
times += 1
val = (val-times)
if val > ord('z'):
val = ord('a') + (val - ord('z')-1)
message +=chr(val)
print("Here is your original message: ", message)

Is this what you're looking for?
word = input("Please enter the encrypted word: ")
message = ""
times = 0
for i in range(58):
message = ""
for ch in word:
val=ord(ch)
val = (val-times)
if val > ord('z'):
val = ord('a') + (val - ord('z')-1)
message +=chr(val)
print("Here is your encrypted message: ", message)
times += 1
Knowing what kind of encryption was used would make this a much easier problem to solve.