65 lines
2.1 KiB
Python
65 lines
2.1 KiB
Python
import base64
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ciphertext=input("Enter message to decode: ")
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steponel = list(ciphertext)
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stepone = ""
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for i in range(len(steponel)-1):
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stepone=stepone+steponel[i]
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steptwo = stepone.encode('utf-8')
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steptwob = base64.a85decode(steptwo)
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steptwoc = steptwob.decode('utf-8')
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def vigenere_dec(cipher,key):
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alphabet = "abcdefghijklmnopqrstuvwxyz0123456789"
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input_string = ""
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dec_key = ""
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dec_string = ""
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dec_key = key
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dec_key = dec_key.lower()
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input_string = cipher
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input_string = input_string.lower()
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string_length = len(input_string)
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expanded_key = dec_key
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expanded_key_length = len(expanded_key)
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while expanded_key_length < string_length:
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expanded_key = expanded_key + dec_key
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expanded_key_length = len(expanded_key)
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key_position = 0
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for letter in input_string:
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if letter in alphabet:
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position = alphabet.find(letter)
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key_character = expanded_key[key_position]
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key_character_position = alphabet.find(key_character)
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key_position = key_position + 1
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new_position = position - key_character_position
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if new_position > 35:
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new_position = new_position + 36
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new_character = alphabet[new_position]
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dec_string = dec_string + new_character
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else:
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dec_string = dec_string + letter
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return(dec_string)
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def stepfour(stepthree):
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stepthree=str(int(stepthree,36))
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test = list(stepthree)
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if len(test)%3==1:
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stepthree="00"+stepthree
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if len(test)%3==2:
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stepthree="0"+stepthree
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stepthreel = list(stepthree)
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stepfourl = [""]*int((float(len(stepthreel))/3))
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k = 0
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while k < len(stepthreel)-2:
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stepfourl[int(k/3)] = stepthreel[k] + stepthreel[k+1] + stepthreel[k+2]
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k = k + 3
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for j in range(len(stepfourl)):
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temp = stepfourl[j]
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temp = int(temp)
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temp = chr(temp)
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stepfourl[j] = temp
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stepfour=""
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for l in range(len(stepfourl)):
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stepfour = stepfour + stepfourl[l]
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return(stepfour)
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key = input("Enter encryption key: ")
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stepthree = vigenere_dec(steptwoc, key)
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stepfour = stepfour(stepthree)
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print("Your decoded message: "+stepfour) |