Question

I want to store hashes as binary (64 bytes). But for any type of API (web service) I would want to pass them around as strings. hashlib.hexdigest() will give me a string, and hashlib.digest() will give me the binary. But if, for example, I read in the binary version from disk, how would I convert it to a string? And if I read in the string from a web service, how would I convert it to binary?

Answer 1

You could start with the string version to pass around and display:

>>> import hashlib
>>> string_version = hashlib.md5(b'hello world').hexdigest()

Convert it to binary to write it to disk:

>>> save_as_binary = string_version.encode('utf-8')
>>> print(save_as_binary)
b'5eb63bbbe01eeed093cb22bb8f5acdc3'

When reading it back from disk, convert it back to a string:

>>> back_to_string = save_as_binary.decode('utf-8')
>>> print(back_to_string)
5eb63bbbe01eeed093cb22bb8f5acdc3