How to reduce a random hash to a boolean value

0 votes

In c or a c-like language assuming I have a random_hash what is the cheapest way to reduce it to a boolean value i.e. 0 or 1?

An example random_hash to normalise answers: 0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa

Restrictions: no method/stdlib calls.

Why c-like, I'm actually trying to do it in a language called Solidity, which is modeled after c/javascript, which has a very limited runtime/stdlib.

Oct 26, 2018 in Blockchain by Prerna
• 1,960 points
546 views

1 answer to this question.

0 votes

Take the largest or smallest bit from the hash and use this as the boolean. Actually, taking any bit should be fine, assuming a good hash function. Assuming the hash is an array of unsigned char, you can use the bitwise AND operator &

(hash[0] & 1) > 0
answered Oct 30, 2018 by Christine
• 15,790 points

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