Python read text file as binary?

Question

I was trying to build an encryption program in python 2.7. It would read the binary from a file and then use a key to encrypt it. However, I quickly ran into a problem. Files like image files and executables read as hex values. However, text files do not using open(). Even if i run

file=open("myfile.txt", "rb")

out=file.read()

it still comes out as just text. I'm on windows 7, not linux which i think may make a difference. Is there any way i could read the binary from ANY file (including text files), not just image and executable files?

Answer 1

Even when reading a file with the 'rb' flag, if your file has the byte '\x41' it will be printed as the letter 'A' in the console. If you want the hex values, encode the file content as hex, which means:

content = open('text.txt', 'rb').read()
# Since python 3.5:
hex = content.hex()
# else:
hex = content.encode('hex')

Answer 2

Take a look at below code .also it has many points for you

from hashlib import md5
from Crypto.Cipher import AES
from Crypto import Random

def derive_key_and_iv(password, salt, key_length, iv_length):
    d = d_i = ''
    while len(d) < key_length + iv_length:
        d_i = md5(d_i + password + salt).digest()
        d += d_i
    return d[:key_length], d[key_length:key_length+iv_length]

def encrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    salt = Random.new().read(bs - len('Salted__'))
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    out_file.write('Salted__' + salt)
    finished = False
    while not finished:
        chunk = in_file.read(1024 * bs)
        if len(chunk) == 0 or len(chunk) % bs != 0:
            padding_length = (bs - len(chunk) % bs) or bs
            chunk += padding_length * chr(padding_length)
            finished = True
        out_file.write(cipher.encrypt(chunk))

def decrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    salt = in_file.read(bs)[len('Salted__'):]
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    next_chunk = ''
    finished = False
    while not finished:
        chunk, next_chunk = next_chunk, cipher.decrypt(in_file.read(1024 * bs))
        if len(next_chunk) == 0:
            padding_length = ord(chunk[-1])
            chunk = chunk[:-padding_length]
            finished = True
        out_file.write(chunk)

Usage

with open(in_filename, 'rb') as in_file, open(out_filename, 'wb') as out_file:
    encrypt(in_file, out_file, password)
with open(in_filename, 'rb') as in_file, open(out_filename, 'wb') as out_file:
    decrypt(in_file, out_file, password)