Python read text file as binary? - file

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)

Answer 3

Your binary file is coming out looking like text because the file is being treated like it is encoded in an 8 bit encoding (ASCII or Latin-1, etc). Also, in Python 2, bytes and (text) characters are used interchangeably... i.e. a string is just an array of ASCII bytes.
You should search the differences between python 2 and 3 text encoding and you will quickly see why anomalies such as you are encountering can develop. Most of the Python 2 version encryption modules use the python byte strings.
Your "binary" non-text files are not really being treated any differently from the text ones; they just don't map to an intelligible coding that you recognize, whereas the text ones do.