Some cryptocurrencies use fixed values in some positions in the resulting hash, like a fixed amount of initial zeros. What fixed positions and fixed values are Facebook Diem using?

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    $\begingroup$ Are you speaking about proof-of-work? $\endgroup$
    – Ievgeni
    Commented Jul 5, 2021 at 13:36
  • $\begingroup$ I wan't to know more about how secure it is. The more fixed values the less variation and less security in the algorithm. $\endgroup$ Commented Jul 5, 2021 at 13:49
  • $\begingroup$ @Ievgeni Yes this is what is commonly called proof-of-work. I am interested in general how proof-of-work limits the hash function. $\endgroup$ Commented Jul 5, 2021 at 15:05
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    $\begingroup$ Actually the leading zeros are more of a side-effect. Mostly it's just that the hash value must be less than a specific value (like $2^{256}/difficulty$). Of course that results in the first digits beeing zero. (but allows for smoother steps) $\endgroup$
    – jjj
    Commented Jul 11, 2021 at 23:06

1 Answer 1


As far as I understood, you are speaking about proof-of-work. But contrarily to what your question said :

Some Crypto currencies use fixed values in some positions in the resulting hash.

It corresponds to proof-of-work. The idea is the following, to guarantee that people which valid a transaction are "real", the have to solve a puzzle, which is basically a preimage of $\{0\}^\lambda\times\{0,1\}^{256-\lambda}$ for a specific hash function (parametrized by the transaction) (you can look this to have more precision : Complexity of Hash mining/signing)

But not all the cryptocurrency are using proof-of-work. And in particular, as far as I understood it's not the case for DIEM

Citation in the white-paper: "Second, this class of consensus protocols enables high transaction throughput, low latency, and a more energy-efficient approach to consensus than “proof of work” "

Link : https://www.diem.com/en-us/white-paper/#the-libra-blockchain

Citation in "The Libra Blockchain" paper:

"To do this, we plan to gradually transition to a proof-of-stake":


  • $\begingroup$ The second link does not point to a page anymore. $\endgroup$ Commented Mar 11, 2022 at 17:15
  • $\begingroup$ @DavidJonsson I didn't find anymore the whitepaper. But I've added another relevant link. $\endgroup$
    – Ievgeni
    Commented Mar 11, 2022 at 19:32

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