Python Affine-Cipher

Question

def afin(day,month,text):

    for i in range(len(text)):
        ascii = text[i] - 96
        y = (day * ascii) + month;
        while(y > 26):
            y -= 26

    sifrelenmiş_harf = y + 96
    sifrelimesaj += sifrelenmiş_harf



text = input("Enter Text:")
day = input("Birth Day:")
month = input("Birth Month:")
print(afin(day,month,text))

Hey, However, whenever I run this script, it comes up with this error:

    ascii = text[i] - 96

    TypeError: unsupported operand type(s) for -: 'str' and 'int'

How do i fix the mistake?

Does this answer your question? [TypeError: unsupported operand type(s) for -: 'str' and 'int'](https://stackoverflow.com/questions/2376464/typeerror-unsupported-operand-types-for-str-and-int) — Joseph Sible-Reinstate Monica, May 03 '20 at 01:04

score 0 · Answer 1 · answered May 03 '20 at 01:22

I believe you are trying to get the ascii value of every element in a text. In order to do any numeric operation, you need to first convert the character to an integer value. One way is to use the below:

ord(text[i]) ### get the ascii character of your text

once you have this, then you could do the operations like:

 ascii = ord(text[i]) - 96

Reference: How to get the ASCII value of a character

Hope this helps

score 0 · Answer 2 · answered May 03 '20 at 01:40

I think you are probably looking at something like this:

def afin(day,month,text):
x = ""
for i in range(len(text)):
    y = (int(day) * ord(text[i])) + int(month);
    y %= 26
    x += chr(y+ord('a'))
return x

text = input("Enter Text:")
day = input("Birth Day:")
month = input("Birth Month:")
print(afin(day,month,text))

A few changes i made here includes

Instead of manually adding 96 use ord
Instead of manually minus 96 use chr
change day and month into integer so that you can compute y
instead of while(y < 26): y-26 just use y %= 26

Take note your value will differ from most as your mod val is 26 but the algorithm should still be somewhat similar to above.

Python Affine-Cipher

2 Answers2