Replacing words in Python? - python

I'm trying to replace the letters in key with the letters in alpha (and vice versa):
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
key = "XPMGTDHLYONZBWEARKJUFSCIQV"
I am trying to change a string to become encoded (and the other way around), so say "Hello" would become "LTZZE". Any idea how to do this? This is my current code:
usrInput = 0
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
key = "XPMGTDHLYONZBWEARKJUFSCIQV"
def menu():
print "SECRET DECODER MENU"
print ""
print "1) Quit"
print "2) Encode"
print "3) Decode"
usrInput = raw_input("What would you like to do?")
return usrInput
def encodeWord():
plain = plain.upper()
length = len(plain)
encode = plain.encode(alpha, key)
return encode
def decodeWord():
coded = coded.upper()
length = len(coded)
decode = coded.decode(key, alpha)
return decode
def main():
keepGoing = True
while keepGoing:
usrInput = menu()
if usrInput == "2":
plain = raw_input("Text you want to be encoded: ")
encodeWord()
print encode(plain)
elif usrInput == "3":
coded = raw_input("Code you need to be decyphered: ")
decodeWord()
print decode(coded)
elif usrInput == "1":
print "Thanks for doing super secret spy stuff with me. No one seems to want to anymore. Goodbye. ):"
keepGoing = False
else:
print "I don't know what to do! Ahhh!"
main()

Note this is a homework assignment for a computer science class. I created the assignment, and I'm aware it's on stack overflow. If you turn it in as your own work, I will know. You will earn a zero for the assignment and we will begin academic misconduct proceedings.
(If you're playing along at home, this is indeed a string manipulation assignment, and explicitly NOT to be considered a good cryptographic practice. We also are not allowing maketrans() for this assignment, because it's a string manipulation and function exercise for beginning programmers.)
If you're really desperate for help, come see me or one of the recitation leaders we're paying to help you.

Use str.maketrans and str.translate. If you use Python 2 this functions are in string (here (maketrans) and here (translate)).
Example (python 3):
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
key = "XPMGTDHLYONZBWEARKJUFSCIQV"
enc = str.maketrans(alpha, key)
usrInput = 'HELLO'
print(usrInput.translate(enc))
Example (python 2)
import string
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
key = "XPMGTDHLYONZBWEARKJUFSCIQV"
enc = string.maketrans(alpha, key)
inp = 'HELLO'
print string.translate(inp, enc)
Output:
LTZZE

Related

Need Guidance with some Python code (Substitute Cypher Python)

I have some code already but I got feedback on how to pass the rest of the criteria but I have no idea how to do it.
Assignment brief:
You are working in a Newspaper office that handles the reports from their journalists. You have been asked to design a program that will be used to help them send confidential reports in that others cannot read as email is not secure, we need to generate an encryption key that they can encode their scoops and documents when sent by email.
The program will need to generate the key. Encode the message, export the key, import a key from another person and decode a message. It will be a simple substitution cipher. The key needs to be made up out of all Alphanumeric Characters and some Special Characters. It will be a single key per session so you will need to save the key if you close the program otherwise you won’t be able to decode those messages used to encode them.
All projects start with planning it is the most important part that can make or break a project so ensure this is carried out correctly
Pass, Merit and Distinction Requirements
What the feedback says to do:
You were asked to import a key and export a key your program doesn't allow this so you would need to resubmit to get Pass4 and Pass6
Code I have done so far below
def run():
x=input("code or decode? ")
if x == "code":
a=list("")
import string
alpha = str("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
message=input("What is your message to encode? ")
x=len(message)
y=0
z=0
for counter in range(x):
y=y+1
letter = alpha.find(message[z:y])
z=z+1
letter=letter+13
if letter > 24:
letter=letter-24
letter=alpha[letter:letter+1]
if counter != x-1:
print(letter,end="")
else:
print(letter)
x=input("type yes to go again? ")
if x == "yes":
run()
else:
input()
else:
a=list("")
import string
alpha = str("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
message=input("What is your message to decode? ")
x=len(message)
y=0
z=0
for counter in range(x):
y=y+1
letter = alpha.find(message[z:y])
z=z+1
letter=letter-13
if letter < 0:
letter=24+letter
letter=alpha[letter:letter+1]
if counter != x-1:
print(letter,end="")
else:
print(letter)
x=input("again? ")
if x == "yes":
run()
else:
input()
run()
I did some research and come up with this.
You can use it as it is or edit it to meet your needs. Hope it helps.
Update.1: The longer the message, the bigger the encryption key will be. One solution for this is to use zlib.compress method in order to shrink the key, and then decompress it when needed.
Update.2: Added the export/import functionality of the encryption key using a Json file (you can of course choose other way of storing data) along with a title assigned to it, so you have the choice to either enter the title or enter the encryption key of the message for decryption. The title is just optional and for simplicity purposes, you can get rid of it if you want to. You'll also notice the code contains lots of if/else statements, that's just so you know where you currently are and what choices you have.
A GUI based would be better.
import string
import json
import os
# A list containing all characters
alpha = string.ascii_letters
def code(title, message, key = 6):
temp_dict = {}
cipher=[]
for i in range(len(alpha)):
temp_dict[alpha [i]] = alpha [(i+key)%len(alpha )]
# Generating the encryption key
for char in message:
if char in alpha :
temp = temp_dict[char]
cipher.append(temp)
else:
temp =char
cipher.append(temp)
# This code is needed to decode the expected message so make sure to save it by any method you want,
# otherwhise it'll generate a random text.
cipher= "".join(cipher)
main_data = {title : cipher}
file_name = "encryption_key.json"
if os.path.exists(file_name):
with open(file_name, "r+") as file:
data = json.load(file)
data[0].update(main_data)
file.seek(0)
json.dump(data, file)
else:
with open(file_name, "w") as file:
json.dump([main_data], file)
print("Encryption code :",cipher)
def decode(cipher, key = 6):
temp_dict = {}
for i in range(len(alpha)):
temp_dict[alpha [i]] = alpha [(i-key)%(len(alpha ))]
# Decoding the message
decoded_text = []
for char in cipher:
if char in alpha :
temp = temp_dict[char]
decoded_text.append(temp)
else:
temp = char
decoded_text.append(temp)
decoded_text = "".join(decoded_text)
return decoded_text
while True:
# There is an optional parameter (key) within the function which you can change according to your preference.
# The default value is 5 and it needs to be the same in both encode and decodefunctions.
x=input('[E]ncode or [D]ecode? answer with "e/d:" ')
if x.lower() == "e":
title = input("Enter the title of the message: ")
message = input("What is your message to encode? ")
code(title, message)
break
elif x.lower() == "d":
file_name = "encryption_key.json"
if os.path.exists(file_name):
with open(file_name, "r+") as file:
data = json.load(file)[0]
else:
print("There is no related file for decryption.")
continue
choice = input('Enter the [T]itle or the [K]ey of the message for decryption. [A]ll to decrypt everything on the file. answer with "t/k/a:" ')
if choice.lower() == 't':
title = input("Enter the title: ")
if title in data.keys():
encryption_key = data[title]
print(decode(encryption_key))
break
else:
print("There is no such title.")
elif choice.lower() == "k":
encryption_key = input("Enter the encryption code related to the message? ")
if encryption_key in data.values():
print(decode(encryption_key))
break
else:
print("There is no such encryption key.")
elif choice.lower() == "a":
decrypt_dict = {}
for k, v in data.items():
decrypt_dict[k] = decode(v)
print(decrypt_dict)
break
else:
print("There is no related file for decryption.")
else:
print("Enter a valid answer.")

My program runs but it doesn't output an Encrypted Message

The code I wrote is a Vignere Cipher encryption program that uses a keyword to encrypt a message. I wrote this code and when I finished it I ran it and it did all it was supposed to but output the encrypted message. See my code below, any help is gratefully received:
ans = False
print(""" *****Hello. Welcome to the Vignère Cipher Encryption Program*****
***This program uses a keyword that is repeated until it
matches the same lenght of the message and then adds its
numerical value to the numerical value of the message and
outputs the encrypted message in alpha.
Please press:
E to Encrypt
D to Decrypt
or double tap enter to quit.
""")
ans=input("What would you like to do now???")
if ans == "E":
plaintext = input("Please enter a message to be encrypted: ").upper()
keyword = input("Please enter a keyword to be used to encrypt a message (alpha only): ").upper()
ciphered = " "
for i in range (len(plaintext)):
char = plaintext[i]
alphakeywordvalue = ord(keyword[i%len(keyword)]) - ord("A")+1
if char.isupper():
if ans == "E" :
value = ord(char) + alphakeywordvalue
if value > ord("Z"):
value -= 26
print ("Your encrypted text is:", ciphered)
elif ans == "D":
plaintext = input("Please enter a message to be dencrypted: ").upper()
keyword = input("Please enter a keyword to be used to dencrypt a message (alpha only(make sure that it is the same keyword used to encrypt the message)): ").upper()
ciphered = " "
for i in range (len(plaintext)):
char = plaintext[i]
alphakeywordvalue = ord(keyword[i%len(keyword)]) - ord("A")+1
if char.isupper():
if ans == "D" :
value = ord(char) - alphakeywordvalue
if value <ord("A"):
value += 26
ciphered += chr(value)
print ("Your decrypted text is:", ciphered)
This is not a good style of writing code. Very shabby and hard to read. You should make methods for individual parts and create a separate main() like section to interact with the user, if required. Engine should be hidden, car body should be polished. Keep them separate. And yes, DO NOT REPEAT YOURSELF
Well, here's my re-written code. Important parts contain the comments. Errors are explained after it..
def encrypt(message, key, direction='E'):
# Look here. There are three arguments. Third one takes 'E' to encrypt
# and anything else to decrypt. You can modify to handle more cases
ciphered = "" # Initialize. You did it almost well
for i in range (len(message)):
char = message[i]
alphakeywordvalue = ord(key[i%len(key)]) - ord("A")+1 # Perfect. We took the key
if direction=='E': # To encrypt
value = ord(char) + alphakeywordvalue
else: # To decrypt
value = ord(char) - alphakeywordvalue
ciphered += chr(value) # chr is the inverse of ord. It gets the character back
# You missed this line
return ciphered
That's it. Now you can write the code to interact with user or other modules. Here's a sample test:-
message = "Hello World"
key = "abc"
print "ORIGINAL : "+message
encoded_message = encrypt(message, key, 'E')
print "ENCRYPTED : "+encoded_message
plain_message = encrypt(encoded_message, key, 'D')
print "DECRYPTED : "+plain_message
Here's the output:
Now you can edit this method to handle more cases like out of ascii range characters etc.
How could it print the encrypted message, the encryption routine never changes ciphered from an empty string.
if ans == "E":
plaintext = input("Please enter a message to be encrypted: ").upper()
keyword = input("Please enter a keyword to be used to encrypt a message (alpha only): ").upper()
1)-> ciphered = " "
for i in range (len(plaintext)):
char = plaintext[i]
alphakeywordvalue = ord(keyword[i%len(keyword)]) - ord("A")+1
2)-> if char.isupper():
3)-> if ans == "E" :
value = ord(char) + alphakeywordvalue
if value > ord("Z"):
value -= 26
4)-> print ("Your encrypted text is:", ciphered)
ciphered set to empty string, is never changed.
You always know char is upper, because you made all the plaintext upper()
You know ans == "E" because you tested it earlier
This print() is so far indented it tries to print every time through the loop

trouble with the vigenere cipher

print ("")
print ("Welcome to Vigenere cipher!")
print ("")
print ("This program will encrypt then offer you a decryption of your message.")
print ("")
print ("Start this off with inputting your message you would like to encrypt.")
m = input("")
print ("")
print ("Now enter your keyword you would like to use. (it must be (" +str(len(m)),"or less letters.))")
k = input("")
if len(k) > len(m):
print ("")
print ("sorry this is an invaild keyword")
print ("Please re-enter your keyword.")
k = input("")
else:
print ("Your keyword is great. Lets keep going")
print ("")
print ("Is this correct?")
print ("")
print("-------\n"
"Message: ",m,"\n"
"Key: ",k,
"\n-------")
print ("")
print ("yes or no")
correct = input ("")
if 'yes'.startswith(correct.lower()):
print("Great! Lets keep going.")
else:
print ("You previously put: " +str(m), " as your message.")
print ("Please re-enter the keyword you wish to use. (it must be (" +str(len(m)),"or less letters.))")
k = input("")
encrypted = ("")
print ("")
for a in m:
print ("The message letters are")
encrypt2 = ord(a)
for b in k:
print ("The keyword letters are")
encrypt = ord(b)
encrypt3 = (encrypt) + (encrypt2)
encrpyted = chr(encrypt3)
print (chr(encrypt3))
I need it to encrypt with the keyword, any help?
p.s it needs to be basic like the code above.
it is for GCSE (UK)
if it needs to have some commands then can you please tell me what they do :) so i can explain it in the task :)
first, failures in your question:
all the code up for a in m: is unnecessary, all that is not part of your problem, your real problem is to encrypt a word using the vigenere cipher's algorithm, this can be replaced by two lines:
message = "ATTACKATDAWN"
key_adj = "LEMONLEMONLE"
or if you prefer
message = "ATTACKATDAWN"
key = "LEMON"
#key_adj and message equal length
key_adj = key + key*((len(message)/len(key))-1) + key[:len(message)%len(key)]
#key_adj is LEMONLEMONLE
Note: i rename the variables so that the people who help you, better understand,
as the input isn't a problem now, i can solve the problem
second, failures in your algorithm:
The most visible fault is using nested for, more isn't better, this complicates your solution, for this problem you need only one for
for a in m:
for b in k:
....
second failure, is the cipher equation .... for example, first letters:
letter_menssage = "A" -> ord("A") = 65
letter_key = "L" -> ord("L") = 76
+141 -> chr(141) = "ì"
with all this explanation , now I can show a solution:
#i use zip function, match letter message with letter key
# (A,L) (T,E) (T,M) (A,O) (C,N) (K,L) etc.
encrypt = ""
for letter_msg, letter_key in zip(message, key_adj):
code_letter_msg = ord(letter_msg)-ord('A')
code_letter_key = ord(letter_key)-ord('A')
encrypt += chr((code_letter_msg+code_letter_key) % 26 + ord('A'))
print (encrypt)
you get:
LXFOPVEFRNHR
explanation equation:
letter_menssage = "A" -> ord("A")-65 = 0
letter_key = "L" -> ord("L")-65 = 11
((0+11)%26 + 65)-> chr(76) = "L"
letter_menssage = "T" -> ord("A")-65 = 19
letter_key = "E" -> ord("E")-65 = 4
((19+4)%26 + 65)-> chr(88) = "X"

Python - Word Scramble Game

While this assignment is past due (I joined the class late unfortunately) I still need to figure it out. I have the following list of words:
abhor:hate
bigot:narrow-minded, prejudiced person
counterfeit:fake; false
enfranchise:give voting rights
hamper:hinder; obstruct
kindle:to start a fire
noxious:harmful; poisonous; lethal
placid:calm; peaceful
remuneration:payment for work done
talisman:lucky charm
abrasive:rough; coarse; harsh
bilk:cheat; defraud
I need to read this file into a dictionary, pick a random key, scramble it, then ask the user to solve it. Unlike other solutions on here, it does not iterate three times, but runs until the user enters 'n'. The code will ask the user after each round if the user wants to continue the game. The user can also type 'hint' to get the definition of the word.
There is a similar question here: (http://www.dreamincode.net/forums/topic/302146-python-school-project-write-a-word-scramble-game-status-complete/) or rather the result of a question, but I am not knowledgeable enough to bridge the gaps and make it work for my purposes. None of the variation on this that I have seen on stack overflow come close enough for me to bridge the gap either, likely because I just don't know enough yet. Before we even start, this code does not yet work at all really, I am pretty lost at this point, so please be gentle. My code so far is below:
import random
from random import shuffle
#Reads the words.txt file into a dictionary with keys and definitions
myfile = open("words.txt", "r")
wordDict = dict([(line[:line.index(":")], line[line.index(":") +1 : -1])
for line in myfile.readlines()])
#print (b)
def intro():
print('Welcome to the scramble game\n')
print('I will show you a scrambled word, and you will have to guess the word\n')
print('If you need a hint, type "Hint"\n')
#Picks a random key from the dictionary b
def shuffle_word():
wordKey = random.choice(list(wordDict.keys()))
return wordKey
#Gives a hint to the user
def giveHint(wordKey):
hint = wordDict[wordKey]
return hint
#Below - Retrieves answer from user, rejects it if the answer is not alpha
def getAnswer():
answer = input('\nEnter your first guess: ')
while True:
if answer.isalpha():
return answer
else:
answer = input('\nPlease enter a letter: ')
def keepPlaying():
iContinue = input("\nWould you like to continue? ")
return iContinue
def scramble():
theList = list(shuffle_word())
random.shuffle(theList)
return(''.join(theList))
#Main Program
if keepPlaying() == 'y':
intro()
shuffle_word()
randomW = shuffle_word()
#scramKey = list(randomW)
thisWord = scramble()
print ("\nThe scrambled word is " +thisWord)
solution = getAnswer()
if solution == thisWord:
print("\nCongratulations")
if solution == 'Hint' or solution == 'hint':
myHint = giveHint(wordKey)
print(myHint)
else:
print("\nThanks for playing")
I have edited this post to ask for new information, though I am not sure if that ishow its properly done. Thanks to the help of those below, I have made progress, but am stuck not on a specific piece.
I have two questions. 1: How can I get the giveHint() function to return the definition of the random key selected by the shuffle_wprd() function. I know what I have above will not work because it is simply returning a string, but it seems like just using a dict.get() function would not get the correct definition for the random word chosen.
2: How can I get the program not to ask the user to continue on the first pass, but to then ask from then on. I thought about using a while loop and redefining the variable during the iteration, but I don't know enough to get it to work properly.
regardless, thank you to those people who have already helped me.
This should help you out a bit, the length seems to be of no benefit as a hint as you can see the length of the scrambled word so I used the definition as the hint,I think you also want to ask the user to guess the word not individual letters:
from random import shuffle, choice
#Reads the words.txt file into a dictionary with keys and definitions
with open("words.txt") as f:
word_dict = {}
for line in f:
# split into two parts, word and description
word, hint = line.split(":")
word_dict[word] = hint
def intro():
print('Welcome to the scramble game\n')
print('I will show you a scrambled word, and you will have to guess the word\n')
#Picks a random key from the dictionary b
def pick_word():
word = choice(list(word_dict.keys()))
return word
#Gives a hint to the user
def give_hint(word):
# return the definition of the word
descrip = word_dict[word]
return descrip
#Below - Retrieves answer from user, rejects it if the answer is not alpha
def get_answer():
while True:
answer = input('Please enter a guess: ')
if answer.isalpha():
return answer
else:
print("Only letters in the word")
def main():
intro()
word = pick_word()
# give user lives/tries
tries = 3
shffled_word = list(word)
# shuffle the word
shuffle(shffled_word)
# rejoin shuffled word
shffled_word = "".join(shffled_word)
# keep going for three tries as most
while tries > 0:
inp = input("Your scrambled word is {}\nEnter h if you want to see your hint or any key to continue".format(shffled_word))
if inp == "h":
print("The word definition is {}".format(give_hint(word)))
ans = get_answer()
if ans == word:
print("Congratulations you win!")
break
tries -= 1
# ask user if they want to play again, restarting main if they do
play_again = input("Press 'y' to play again or any key to exit")
if play_again == "y":
main()
# else the user did not press y so say goodbye
print("Goodbye")
main()
There are a few more bits to be added but I will leave that up to you.
Thank you to all those who helped. For any who come along later, the final product is here. Similar to what Padraic Cunningham put, but without the three answer limit, and without his more elegant solution of wrapping the main program into a called function.
import random
from random import shuffle, choice
#Reads the words.txt file into a dictionary with keys and definitions
with open("words.txt") as f:
wordDict = {}
for line in f:
# split into two parts, word and description
word, hint = line.split(":")
wordDict[word] = hint
#print (b)
def intro():
print('Welcome to the scramble game\n')
print('I will show you a scrambled word, and you will have to guess the word\n')
print('If you need a hint, type "Hint"\n')
#Picks a random key from the dictionary b
def shuffle_word():
wordKey = choice(list(wordDict.keys()))
return wordKey
#Gives a hint to the user
def giveHint(wordKey):
descrip = wordDict[word]
return descrip
#Below - Retrieves answer from user, rejects it if the answer is not alpha
def getAnswer():
answer = input('\nEnter a guess: ')
while True:
if answer.isalpha():
return answer
else:
answer = input('\nPlease enter a letter: ')
def getAnswer2():
answer2 = input('\nEnter another guess: ')
while True:
if answer2.isalpha():
return answer2
else:
answer2 = input('\nPlease enter a letter: ')
def keepPlaying():
iContinue = input("\nWould you like to continue? ")
return iContinue
#def scramble():
# theList = list(shuffle_word())
# random.shuffle(theList)
# return(''.join(theList))
#Main Program
while keepPlaying() == 'y':
intro()
#shuffle_word()
randomW = shuffle_word()
cheatCode = giveHint(randomW)
#scramKey = list(randomW)
thisWord = list(randomW)
print(thisWord)
random.shuffle(thisWord)
print(thisWord)
thisRWord = ''.join(thisWord)
print ("\nThe scrambled word is " +thisRWord)
solution = getAnswer()
loopMe = False
while loopMe == False:
if solution == randomW:
print("\nCongratulations")
loopMe = True
if solution == 'Hint' or solution == 'hint':
print(cheatCode)
if solution != randomW:
loopMe = False
solution = getAnswer2()

Moving a string forward in the alphabet?

I have been asked just as a challenge to create a program of which encrypts an input. I have looked into creating a program but there isn't much around on how to do it. It seems like it shouldn't be too complicated, but I haven't been taught any of it in my lessons. I read this post too Get character position in alphabet but didn't have much luck! I have this so far:
import sys
import os
import time
import string
def Cryption():
####################
encrypt = 'encrypt'
decrypt = 'decrypt'
####################
s = raw_input("Would you like to encrypt or decrypt? Enter your answer")
if encrypt in s:
print("Loading encryption sector...")
time.sleep(2)
enc = raw_input("Please input the string you would like to encrypt")
print ("Your decrypted word is: " + enc)
if decrypt in s:
print("Loading decryption sector...")
time.sleep(2)
dec = raw_input("Please input the string you would like to decrypt")
else:
print("Your input was invalid, please re-enter your choice!")
r = raw_input("Press enter to restart your program")
Cryption()
Cryption()
I was thinking if I took the input added 5 onto each letter value then re-printed the product. Which functions would I use to add 5 onto the order in the alphabet? ord()? And if so could someone point me in the direction of how to use it? Thanks in advance!
import string
def encrypt_s(shift):
lower = string.ascii_lowercase
# shift forward current index of each character + the shift
dict_map = {k:lower[(lower.index(k)+shift)%26] for k in lower}
return dict_map
def decrypt_s(shift):
lower = string.ascii_lowercase
# shift forward current index of each character - the shift to get original string
dict_map = {k:lower[(lower.index(k)-shift)%26] for k in lower}
return dict_map
def Cryption():
####################
encrypt = 'encrypt'
decrypt = 'decrypt'
####################
s = raw_input("Would you like to encrypt or decrypt? Enter your answer")
if encrypt in s:
print("Loading encryption sector...")
time.sleep(2)
enc = raw_input("Please input the string you would like to encrypt").lower()
enc_s = encrypt_s(5)
enc = "".join([enc_s[char] if char in enc_s else char for char in enc])
print ("Your encrypted word is: ",enc)
elif decrypt in s:
print("Loading decryption sector...")
time.sleep(2)
dec = raw_input("Please input the string you would like to decrypt").lower()
dec_s = decrypt_s(5)
dec = "".join([dec_s[char] if char in dec_s else char for char in dec])
print ("Your decrypted word is: ",dec)
else:
print("Your input was invalid, please re-enter your choice!")

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