Question

1. Write a python program:
2. Ask for the encryption key.
   • The key must be a list of numbers between 0 and N-1, where N is the number of entries in the key's list; for example, 5,4,3,2,1,0 has six numbers, and each digit 0-5 appears in the list.
3. Asks for a line of text to encrypt.
4. Use the transposition key to transpose each chunk of N letters in input text.
   • If the input text is not a multiple of the key length, then pad the input with .. For example, if the key is 5,4,3,2,1,0 and the input is HelloMIS!, then add three . to make the input line a multiple of 6, like HelloMIS!...
   • Hint: You might slice batches of N characters out of the input string and loop over the indexes in the key to determine which characters to print out of each batch
5. Output the encrypted result.
   • If the the key is 5,4,3,2,1,0 and the input text is HelloMIS!, then the output should be MolleH...!SI
   • Or, If the key is 4,3,2,1,0 and the input text is HelloMIS!, then the output should be olleH.!SIM

• Show an error and exit the program if the encryption key does not have the numbers 0 though N-1 (where N is the number of values in the key).

An easy way to verify correct operation of the program is to use the encryption key 0, which should give the same string in the output as in the input. Another simple test is the encryption key 1,0, which will reverse each pair of input characters.

Examples of the program's run:

$ python transpose.py 
Enter key (comma-separated list of numbers)): 5,4,3,2,1,0
Enter text to encrypt: HelloMIS!
Encrypted text: MolleH...!SI

$ python transpose.py 
Enter key (comma-separated list of numbers)): 4,3,2,1,0
Enter text to encrypt: HellowMIS!
Encrypted text: olleH!SIMw

$ python transpose.py 
Enter key (comma-separated list of numbers)): 6,4,3,2,1,0
Error: key 6 is not valid (must be between 0 and 5)

$ python transpose.py 
Enter key (comma-separated list of numbers)): 4,3,2,1,0,0
Error: number 5 must be in the key

$ python transpose.py 
Enter key (comma-separated list of numbers)): 5,3,4,2,0,1
Enter text to encrypt: Our liberties we prize and our rights we will maintain.
Encrypted text: i lrOuetirbepe ws ae zrirou ndtghi rwe ws a mlilnaitin......

$ python transpose.py 
Enter key (comma-separated list of numbers)): 4,5,3,1,2,0
Enter text to encrypt: i lrOuetirbepe ws ae zrirou ndtghi rwe ws a mlilnaitin......
Encrypted text: Our liberties we prize and our rights we will maintain......

Answer 1

#source code:

while(True):
   key=list(map(int, input("Enter key (comma-separated list of numbers)):").split(",")))
   new_list = key.copy()
   k=len(key)
   error=[]
   sub=key
   encrypt=""
   for i in range(len(key)):
       if i in sub:
           sub.remove(i)
       else:
           error.append(i)
      
   if(len(sub)==0 and len(error)==0):
       pass
   else:
       if(len(sub)==0 and len(error)!=0):
           print("Error: {} These elements are not present in the input range".format(error))
       elif(len(sub)!=0 and len(error)==0):
           print("Error: {} These elements outside given range".format(sub))
       else:
           print("Error: {} These elements are not ptreset in the input".format(error))
           print("Error: {} These elements outside given range".format(sub))
       continue
   enc=input("Enter text to encrypt: ")
   check=len(enc)
   if((check%k)==0):
       pass
   else:
       j=check-1
       while(j%k!=0):
           enc=enc+"."
           j=j+1
   new_txt=""
   string_list=[]
   for i in range(1,len(enc)+1):
       new_txt+=enc[i-1]
       if(i%k==0):
           string_list.append(new_txt)
           new_txt=""
       else:
           pass
   for i in range(len(string_list)):
       for j in range(len(new_list)):
           encrypt+=string_list[i][new_list[j]]
   print("Encrypted text: ",encrypt)
   break
  

      
      
  
          
      

#output:

#if you have any doubts comment below..if you like give thumbs up...