Decentralized Technology - Discussion

Welcome to the discussion about this lecture. Here you can ask questions or post feedback about this specific lecture.


Hi Filip, You had mentioned in this segment about a quiz. Can you direct me to that please, I don’t see it listed. The next segment is a reading assignment and not listed there. Thank you.

Enjoying your content. Explained well.


I will look into why that’s missing. Thanks.

Hi there.

I do see a quiz at the end of the section. Is that the one you are referring to maybe?

Hi Filip, I thought CORDA wasn’t a Blockchain, am I wrong ?

What I have seen, it is a blockchain. Or at least a blockchain platform, like hyperledger.

1 Like

You mentioned about quiz in Permissioned vs Permissionless video…No quiz there ??

Yes, my mistake. When I made the videos I said “DO THE QUIZ” in so many videos, then I realized we can’t have quizzes all the time. So do the quizzes when you see them and don’t listen to me :smiley:


At this point… in videos there are only slides…why didn’t you make videos as you do on youtube ?..It feels boring after sometime as there is nothing to focus…only listening…

Thank you for the feedback. I will attempt to do them better in the future.

1 Like

Hi @filip and @ivan, hopefully not too stupid questions,

  • Is a decentralized database the same as a permissioned blockchain?
  • what is the benefit to use a permissioned (private) blockchain vs. a database? I mean is the difference only that we are in ‘append only’ mode and cannot modify the data? or do some super-users have modify power in the private blockchain too?



@Fabrice maybe you know? :slight_smile:

1 Like

Absolutely not.

  1. No, not necessarily. Because a permissioned blockchain could in theory be completely centralized with only one node running it. But there is probably some overlap between the two types generally. But it can’t be assumed.

  2. That’s difficult to answer, since there are so many different database types and blockchain systems. But generally I would say the permissioned blockchains are more focused on append-only systems even though it doesn’t have to be. The creator(s) of the permissioned blockchain could define the rules themselves, even to the point of allowing modifications of old data.

1 Like

thanks for replying, so still not sure: what would be the advantage of a centralized and modifiable private blockchain vs a database?

I didn’t say there is an advantage, but I answered your very specific question. Which was if they are the same. But no, I see no advantage in running a centralized and modifiable blockchain.

I think hyperledger is very interesting! it offers a good solution to many problems. (especially today)


You’re missing a bit of details as it is more nuanced than permissioned vs permissionless. You also have public vs private meaning you are not only looking at 2 sides but a quandrant like the following:

1 Like

Yeah that’s one way of looking at it, with some more nuance indeed. But it depends on your definitions. I’m not sure I would agree for example that EOS is permissioned. I can still use eos without permission. I can’t do that with IBM Maersk.

I do agree with you that the projects/companies put into the boxes might not be correct. I was just looking at finding something visual for the explanation purpose.

I just had a talk with Marta Piekarska (from Hyperledger) a while back, and she is pro the concept of first looking at as Public vs Private (anyone can join the chain vs requires invitation to join) and Permissionless vs Permissioned (anyone within can Read&Append vs requires permission to Read&Append).

In that regard I think it makes sense that there are those possible scenarios. While I will not start being an expert on what is what of the projects, I do think it makes sense to look at it as more then 2 scenarios. Perhaps it is just 3 (maybe 4) depending on the way a person it looking at it e.g. public, consortium, private. The lines are a but blurry in that sense, but I would not call Ripple a private chain, nor would I say it is the same sense of public permissionless as Bitcoin is.

The lenght of my reply probably also indicates that it is not that simple a topic, to be fair to you :slight_smile: You didn’t say anything wrong, I would just state that there are something in between.

1 Like

Thanks for the nuance, it’s def not black & white.