CODEWITHSUNDEEP
pythonpython-3.xcrc32
Bouncer00
Bouncer00

Reputation: 123

CRC32 of binary string/binary data in python

I want to get CRC32 of string which contains binary data. I tried to use somethink like this:

binascii.crc32(binascii.a2b_uu(my_binary_string))

But it often throws exceptions for larger strings. Example content for my binary string:

my_binary_string = "0100101010..."

It can be really long. How can I do this ?

Upvotes: 0

Views: 4682

Answers (2)

Ajay
Ajay

Reputation: 5347

for python 3 your binary in python3 should be b'10001', should be prefixed with b or B to denote bytes literal:

In [11]: a=b'10000011110'

In [17]: hex(binascii.crc32(a))
Out[17]: '0xfc8e2013'

Upvotes: 1

James Buck
James Buck

Reputation: 1640

Ajay's answer is incorrect as it treats the binary data as a literal string - each 1 or 0 gets encoded into a separate byte.

Assuming your data is binary from UTF-8 encoding or just bytes concatenated into a long string, you should instead do something like this:

import binascii
data = '0110100001100101011011000110110001101111' # 'hello' encoded in UTF-8
int_arr = [int(data[i:i+8], 2) for i in range(0, len(data), 8)] # split the data into 8-bit chunks
print(hex(binascii.crc32(bytes(int_arr))))

# output = 0x3610a686

which will encode each 8 bits of the string correctly.

Upvotes: 1

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