diff --git a/encryptDecrypt.py b/encryptDecrypt.py
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+#Student Name Mateusz Apanel
+#Student ID 18012102
+#this coursework is based on a project i did in school a few years back in c# and now re done in python.
+
+
+def offset(chars):
+ s1=sum(chars)
+ #Adds all chars ASCII numbers together
+ s2=s1/8
+ #Divides result by 8
+ s3=round(s2)
+ #Rounds result
+ offsetFactor=s3-32
+ print("Offset Factor:", offsetFactor)
+ return offsetFactor
+ #Sets the offset factor as the result -32 before printing and returning it
+
+
+#ENCRYPTION
+def Encrypt(message, offsetFactor):
+ #Arguments are the plainFile text and the offset factor
+ plainFile=message.readline()
+ print("Original text:",plainFile)
+ #Reads the line from the file and prints it
+ plainFile2=[]
+ cipher=[]
+ #Initialises the above arrays
+ i=0
+ for i in range(0,len(plainFile)):
+ if plainFile[i]!=" ":
+ plainFile2.append(plainFile[i])
+ #Adds all characters from text file to array except spaces.
+ for i in range(0, len(plainFile2)):
+ if i%5==0:
+ plainFile2.insert(i," ")
+ #If i is a multiple of 5, inserts a space in the array at that position
+ for i in range(0,len(plainFile2)):
+ if plainFile2[i]!=" ":
+ char=ord(plainFile2[i])+offsetFactor
+ #Encrypt the letter for the length of the text file
+ if char>126:
+ char-=94
+ #If it is above the ASCII range, minus 94
+ cipher.append(char)
+ #Adds the char to the cipher text array
+ else:
+ cipher.append(ord(" "))
+ print(cipher)
+ cipherText=""
+ #Initialises the cipherText variable
+ for i in range(0,len(cipher)):
+ cipherText=cipherText+chr(cipher[i])
+ #Adds all of the chars of the cipher text to the string
+ return cipherText
+ #Returns the cipher text string to the function
+
+
+def EncryptMessage():
+ fileValid=False
+ while fileValid==False:
+ fileName=input("Please enter the name of your file\n") #sample.txt
+ if os.path.isfile(fileName):
+ fileValid=True
+ file=open(fileName, "r")
+ #Opens the file to be encrypted if it exists
+ else:
+ print("This file does not exist")
+ i=0
+ chars=[0,1,2,3,4,5,6,7]
+ nChars=[0,1,2,3,4,5,6,7]
+ #Initialises the above arrays
+ for i in chars:
+ nChars[i]=random.randint(33,126)
+ #Generates a random number within the ASCII range
+ chars[i]=chr(nChars[i])
+ #Converts the random number to a character before storing in the array
+ i+=1
+ key="'"
+ for i in range(0,8):
+ key+=chars[i]
+ key+="'"
+ print("\nKeep this key safe for decryption:", key)
+ #Sets the key to the array and prints it as a string
+ offsetFactor=offset(nChars)
+ #Carries out the offset factor calculation
+ cipherText=Encrypt(file, offsetFactor)
+ #Begins encryption process
+ print("Encryption Complete:", cipherText,"\n")
+ outputFileName=input("Please enter the name of the output file\n")
+ outputFile=open(outputFileName, "w")
+ outputFile.write(cipherText)
+ print("File written")
+
+
+
+
+#DECRYPT MESSAGE
+def decrypt(message, offsetFactor):
+ #Arguments are the cipher text and the offset factor
+ cipher=message.readline()
+ print("Encrypted text:",cipher)
+ #Reads the line from the file and prints it
+ plainFile=[]
+ #Initialises plainFile text array
+ for i in range(0,len(cipher)):
+ if cipher[i]!=" ":
+ char=ord(cipher[i])-offsetFactor
+ #For the length of the text, if char isn't space, decrypt letter
+ if char<32:
+ char+=94
+ #If it is below the ASCII range, plus 94
+ plainFile.append(char)
+ #Adds the char to the plainFile text array
+ else:
+ plainFile.append(ord(cipher[i]))
+ #Adds the space to the plainFile text array
+ plainText=chr(plainFile[0])
+ #Adds the 1st letter of the plainFile text to the string
+ for i in range(1,len(plainFile)):
+ plainText=plainText+chr(plainFile[i])
+ #Adds the rest of the chars of the plainFile text to the string
+ return plainText
+ #Returns the plainFile text string to the function
+
+
+def DecryptMessage():
+ fileValid=False
+ keyValid=False
+ while fileValid==False:
+ fileName=input("Please enter the name of your file\n")
+ if os.path.isfile(fileName):
+ fileValid=True
+ file=open(fileName, "r")
+ #Opens the file to be decrypted if it exists
+ else:
+ print("This file does not exist")
+ while keyValid==False:
+ sKey=input("Please input your 8 character key")
+ if len(sKey)==8:
+ keyValid=True
+ else:
+ print("Invalid key detected")
+ #Asks user to input key as string
+ i=0
+ key=[0,1,2,3,4,5,6,7]
+ nKey=[0,1,2,3,4,5,6,7]
+ #Initialises above arrays
+ for i in key:
+ nKey[i]=ord(sKey[i])
+ #Converts string into ASCII number and stores in array
+ key[i]=chr(nKey[i])
+ #Converts ASCII number to character and stores in array
+ i+=1
+ offsetFactor=offset(nKey)
+ #Carries out offset factor calculation
+ plainText=decrypt(file, offsetFactor)
+ #Begins decryption process
+ print("\nDecryption Complete:", plainText,"\n")
+ #Prints decrypted file
+
+#MAIN MENU
+import time
+import random
+import os
+#Imports the random and time modules for later use.
+offsetFactor=0
+cipherText=""
+#Initialises the above variables
+def menu():
+ choice=0
+ while choice != 1|2:
+ print("Option 1: Encrypt Message\n")
+ print("Option 2: Decrypt Message\n")
+ print("Option 3: Exit\n")
+ #Displays the valid menu options
+ choice = int(input("Please type in 1, 2, 3 to choose an option.\n"))
+ #Gets the user to choose an option
+ if choice == 1:
+ EncryptMessage()
+ elif choice == 2:
+ DecryptMessage()
+ #Redirects the user to the correct function
+ time.sleep(1)
+ exit()
+ #Closes the program if the user chooses option 3 or other
+menu()
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