0

i have a code that encrypts data and then i embed it into an image, so when I was checking the encryption and decryption code that worked fine, Also i used blowfish module for encryption.

now problem is that when I embed the data into the image and extract it, It's a bytesarray in plaintext form,

b'\x98\xac\xc3ymQ_\x80\xcb\xec\x9c\x04\xc3@\x88\x93`j\x05\x96\x9d\xcb\x0ec\xb2\x9b(\xd9@\x9fI\x00\xc7h\xe3\x83\xbd0\r\xad}*t'

the above is a bytesarray in plaintext form, So if I try to convert it to bytesarray again it will re-encode it and put the '\' between the characters that already have it and now this new bytesarray is not a normal bytesarray, and the data is corrupted.

bytearray(b"b\'\\x98\\xac\\xc3ymQ_\\x80\\xcb\\xec\\x9c\\x04\\xc3@\\x88\\x93`j\\x05\\x96\\x9d\\xcb\\x0ec\\xb2\\x9b(\\xd9@\\x9fI\\x00\\xc7h\\xe3\\x83\\xbd0\\r\\xad}*t\'")

So my question is that how do I typecast or convert the str to a bytesarray? without changing the data.

Improve this question
3
  • 1
    You can use eval(expr) to achieve that. Be warned, though, that this can by made to execute any code, so make sure you know what you submit to it. Also, I think you shold try to understand why you get the result as a string. If you can, it is better to fix this at the source. Commented Jun 26, 2021 at 7:04
  • ohh that, i purposefully made it to a string so that i can convert it to binary. Commented Jun 26, 2021 at 8:36
  • Please edit your question to share a minimal reproducible example. Where your string comes from? Maybe it's a XY problem and could be prevented rather than solved? Commented Jun 26, 2021 at 11:07

2 Answers 2

Reset to default
1

If I can understand your requirement then the following code snippet could help. Applied module ast — Abstract Syntax Trees:

import ast

bys=r"b'\x98\xac\xc3ymQ_\x80\xcb\xec\x9c\x04\xc3@\x88\x93`j\x05\x96\x9d\xcb\x0ec\xb2\x9b(\xd9@\x9fI\x00\xc7h\xe3\x83\xbd0\r\xad}*t'" print( '↓↓↓', type(bys)) print( bys) byb = ast.literal_eval(bys) print( byb) print( '↑↑↑', type(byb))

Result: .\SO\68139330.py

↓↓↓ <class 'str'> b'\x98\xac\xc3ymQ_\x80\xcb\xec\x9c\x04\xc3@\x88\x93`j\x05\x96\x9d\xcb\x0ec\xb2\x9b(\xd9@\x9fI\x00\xc7h\xe3\x83\xbd0\r\xad}*t' b'\x98\xac\xc3ymQ_\x80\xcb\xec\x9c\x04\xc3@\x88\x93`j\x05\x96\x9d\xcb\x0ec\xb2\x9b(\xd9@\x9fI\x00\xc7h\xe3\x83\xbd0\r\xad}*t' ↑↑↑ <class 'bytes'>
Improve this answer
Sign up to request clarification or add additional context in comments.

2 Comments

Ok so as the JohanL said i used eval now a new problem arose, apparently eval has some memory limitations and hence it breaks when the byte string is a certain length does literal_eval has that problem covered?
It doesn't work, is there a manual way of doing it, i get eol error because the byte string is too long.
0

Okay anyone else trying to achieve this the other answers are correct provided you are working with a small byte string.

But as I wasn't and needed the theoretical unlimited byte string size (I wanted it to be at-least 1000 lines of 25 words of 4 letters on average each).

So if you want to do the same then, convert the Byte string to it's equivalent binary by below code:

def bitstring_to_bytes(s): return int(s, 2).to_bytes((len(s) + 7) // 8, byteorder='big')

Then reconstruct the byte string by

def bin2byte(bin_string): return bin(int.from_bytes(bit_string, byteorder="big"))

this can overcome the limitation with eval and can go way further than that.

I referred these posts from stack overflow: byte string to binary: How can I convert bytes object to decimal or binary representation in python?

binary to byte string :Convert binary string to bytearray in Python 3

Improve this answer

Comments

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.