Syntax to use combination of two hash algorithm

Question

I would like to know how to write in a single line the combination of two hash algorithms in Python. I want to use MD5 and sha256 in one line. Here is my function:

def calcHash(self):
    block_string = json.dumps({"nonce":self.nonce, "tstamp":self.tstamp, "output":self.output, "prevhash":self.prevhash}, sort_keys=True).encode()
    return hashlib.sha256(block_string).hexdigest()

I tried return md5.hashlib(hashlib.sha256(block_string).hexdigest()) but it doesn’t work.
Can someone help?

Asked By: someone

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Answer 1

The problem could just be that .hexdigest() produces a string, not a bytes, so you need to encode it again

>>> import hashlib, json
>>> j = json.dumps({"foo":"bar","baz":2022})
>>> hashlib.sha256(j.encode()).hexdigest()
'44ce0f46288befab7f32e9acd68d36b2a9997e801fb129422ddc35610323c627'
>>> hashlib.md5(hashlib.sha256(j.encode()).hexdigest().encode()).hexdigest()
'f7c6be48b7d34bcd278257dd73038f67'

Alternatively, you could directly use .digest() to get bytes from the hash, rather than intermediately converting it to a hex string (though note the output is different)

>>> hashlib.md5(hashlib.sha256(j.encode()).digest()).hexdigest()
'12ac82f5a1c0cb3751619f6d0ae0c2ee'

If you have a great many algorithms in some order, you may find .new() useful to iteratively produce a result from some list of hashes.

BEWARE
md5 is broken from a security perspective and I cannot recommend using it unless it’s a required input to a legacy system!

Answered By: ti7

Syntax to use combination of two hash algorithm

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