Pierre explains PARSEC

already made a few more slides (I’m at about 50 now). So 20 or so more to go


Indeed, thanks for your work @Eureka18. I like the slides too. I couldn’t use them as is though as they were created in powerpoint and don’t render nice in Libre Office. (I don’t run Windows)
Thinking out loud here: I think it would be nice if we could take inspiration from these slides to create a Google Slides theme that would then be recommended when creating such a slide show. That way, from the next presentation on, we could benefit from this work while not adding massive overhead compared to what we would have done anyway.


I agree, consistency/efficiency are the way forward here. We’ve had some chat within the team about getting a SAFE Network style for presentations over the past few months. The original plan was to start by building this into the resources available for SAFE Network Meetup organisers as well (we already have a style on the brand assets page on the website - https://www.maidsafe.net/assets.html - but this is a little outdated currently) and it was discussed in the last meetup organisers call with @Sotros25 etc.


Sounds like something that perhaps could be implemented with entangled photons, then it would be truly random, yet all observers would observe the same state. Would have to wait a couple decades until today’s prototype quantum networks are made into a full blown global quantum internet before that could be a useful solution though.


I’m circling back here to share some updates. The general takeaway is that PARSEC is obviously a serious innovation as there was generally no mortal negative feedback, but everyone seems too focused on their own killer protocol and (let me be careful with this one) might not really want to help a competing protocol, regretfully.
– One person could not comment too openly because of ongoing IPs around similar concepts.
– The second completely avoided discussing PARSEC.
– The third had a lot to say, but I felt their take on PARSEC was not fully objective or actionable. This person wanted more details about the assumptions being made (fair enough as others had similar feedback) and worried that design might be taking precedent over rigor. Where I really disagreed was the suggestion that one should stick to the only true and tested approaches (how are better approaches ever going to be developed if no one tries to do things differently?) Still, I’m grateful that this person took time to provide as much feedback as they did.

Forgive that I cannot provide more details than this on a public forum at this time as these people spoke confidentially for now. I’m still pushing for more engagement.


Thanks for the updates, always good to hear everything we can from those who may have some critical input. Shame about IP, it really is an anathema of progress, but we take what we can anyway. The best thing right now is the work in this area is really expanding as well as interesting takes on POS (which I am not a fan of yet, as I cannot see why the rich get more power than the poor) and zksnarks (like corda [EDIT sorry meant coda Coda: Keeping Cryptocurrency Decentralized | by Mina Protocol | MinaProtocol | Medium ) IIRC).

As I have said previously, I don’t care who progresses this space, as long as it progresses as the existing model is illogical and panders to horrendous business models. The models create money though and that is hard to defeat as a majority of humans seem swayed by “money for nothing” mentalities and forget the children, inventors, and generations to follow, that all need space to breathe and be free.

Again though, great to hear some feedback. We do really need to provide more on the concrete coin (although others ignore this part, which is weird). Thanks again.


Someone posted on here from the Nano discord that they are investigating PARSEC. Would these be some of the contacts mentioned?? If not, then there are even more eyes on it. As the testing comes along and the paper refined it will only strengthen the case for PARSEC.

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I could not agree more. We have all been incentivized to play and win by these old rules. Many who partake in the current system/model do lament its workings though often do nothing to change it. Worse still, there are wolves that will use these old rules to stifle progress and ensure that they keep getting more and more to the detriment of everyone else. It’s also not lost on me that many of us complain about these models only to later ensure their continuation once our own breads are buttered! Human nature as they say – it’s why the autonomous side of the Safenetwork is so so critical.

Anyway, if the transition from these old models is to be successful, it’s important that we understand the old rules and leverage them when/if needed (e.g., IP). Finally, definitely no need to thank me. Anything I can do to help here I will gladly do. Safenetwork is a very important project for humankind.


I can confirm that my contacts are more traditional (i.e., not Nano or other cryptos). Fully agree re: “As the testing comes along and the paper refined it will only strengthen the case for PARSEC”.


This is an awesome video, a REAL shame it was not published in tandem with the whitepaper. It would have solidified the idea much deeper into the “outsiders” mind who happened to take a look due to the paper.

This problem is essentially what PARSEC solves. It makes it possible to reach 100% certainty consensus with no reliance on timing, with up to 1/3 of the network being dishonest even if the network is attacked (up to 1/3 is the most any network can endure).

From flatoutcrypto.com … congrats Maid team!!


Sorry to revive this old topic, but this indeterminism still bothers me. The following initial state is used in many PARSEC presentations:

The problem is that this situation is not in the domain of validity of PARSEC because there are two nodes with an estimate of true and two with false. This means there are necessarily two malicious nodes here, which is above the 1/3 PARSEC threshold.

The common coin will allow reaching an agreement, but there is a 50% chance that the decided value will be the one proposed by the malicious nodes. I think this is an obstacle for users to understand the protocol, and this certainly confused me.

Now, I will rephrase my original question: Is the common coin protocol only needed to unblock the algorithm outside PARSEC domain of validity or are there cases where it is also needed within this domain (with less than one 3rd of malicious nodes)?


This estimates are not final votes about an event but meta votes. Meta votes are the answer about the question “Do I strongly see an interesting gossip event for this node?”. In this case Alice and Dave strongly see an interesting event and Bob and Carol not.


Ok. But now I have an even more basic question for @maidsafe: how do we get this situation highlighted in my post and mentioned in many PARSEC presentations?

Suppose there is a real network event (for example Frank wants to join the network) but some malicious nodes don’t want it to be recorded. I see the following cases but none of them lead to this situation.

  • If all nodes are honest then the 4 nodes will strongly see this event.
  • If one node is malicious then the 3 honest nodes will strongly see the event
  • If two nodes are malicious then no nodes will strongly see the event because the 2 honest nodes don’t make a super majority
  • Same for 3 and 4 malicious nodes
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2 of 4 is less than a superiority if your group size is 4 (which is what I think you are seeing). Use of 1, 2 or 3 in some maths is a it misleading. If you start at a group size of 8 or similar it becomes more clear.

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There is no group size in PARSEC, because the whole network is a section.

But this eludes the question, I just want to know how we can get the following example used in many PARSEC presentations:

and described with words by @digipl:

In this case Alice and Dave strongly see an interesting event and Bob and Carol not.

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Maybe it’s easier to explain than with 8 or 1008

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In Dave’s case is evident. Bob->Carol->Dave (Dave sees, at least, 3 of 4 nodes that form a supermajority).

In Alice’s case a previous gossip makes a path that forms a supermajority.

For example Carol->Bob->Alice or Dave->Bob->Alice.

We also know that neither Bob or Carol can see a path that pass through more than two nodes.


That’s a good question. It comes from a misunderstanding of the problem space:
Honest nodes can vote for true or false. It is not malicious to vote for something another honest node didn’t vote for.

Let me give you an example (with a bit of a metaphore):
You could use binary consensus to have people all over the planet agree on the question: “Did it rain on this specific day?” Each honest node would report on the weather conditions they observed where they live. Honest nodes would definitely say the truth, but all honest nodes may not have experienced the same reality, because it may have rained in some parts of the world but not in others. Malicious nodes may vote contrary to what they experienced (if it’s advantageous to impede consensus).

The outcome of binary consensus will be either “yes” or “no”. All honest nodes will have the same outcome. If the outcome is “yes”, you can be sure that it rained in at least one place where a honest node was observing the weather. If the outcome is “no”, you can be sure that it didn’t rain in at least one place where a honest node was observing the weather.

What’s malicious is not to disagree but to report fake information (probably with the purpose of causing nodes to agree on a fake value or with the purpose to delay consensus forever).

I hope this clarifies it :smile:


Hi @pierrechevalier83, a contextual question regarding the use of the word “byzantine” in the name and definition of a consensus algorithm:

An algorithm being “byzantine” meaning that it’s liar proof, right.

So, 2/3 must be sincere. Say these are split 50-50 of the 66.6%, meaning 33.3% vote YES and 33.3% vote NO.

Parsec can’t read the minds of the remaining 33.3% liars.

If the liars are allowed to vote as they want, they can tip over 50% both for the YES and the NO side. (33.3% genuine participants’ YES + 33.3% YES votes from the liars = 66.6% YES vote, which is above the >50% majority threshold, same for the NO side - 33.3% genuine participants’ NO + 33.3% NO votes from the liars = 66.6% NO vote.)

Absent of being able to read people’s minds, what does Parsec do to to separate the wheat from the chaff & get to some kind of honest participants’ vote?

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