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Making CRDTs Byzantine Fault Tolerant [pdf]

martin.kleppmann.com

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Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#2
Martin's writing and explanation style is truly awesome! I read his book DDIA (Designing data intensive applications) and listened to his distributed systems class lectures [1]. It was a joy learning. I wish I had him or someone like him in graduate school. I would've probably taken all his courses :-).

[1] https://www.youtube.com/watch?v=UEAMfLPZZhE&list=PLeKd45zvjc...

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#3
post #2

Martin's writing and explanation style is truly awesome! I read his book DDIA (Designing data intensive applications) and listened to his distributed systems class lectures [1]. It was a joy learning. I wish I had him or someone like him in graduate school. I would've probably taken all his courses :-). [1] https://www.youtube.com/watch?v=UEAMfLPZZhE&list=PLeKd45zvjc...

Seriously. My advice to all, if you see "Kleppmann", click the link.

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#4
Woah. This paper looks freaking awesome - and surprising! “The proposed scheme can tolerate any num- ber of Byzantine nodes (making it immune to Sybil attacks)” - this is really intriguing because of the strong impossibility results in consensus algorithms around how many faulty nodes can be tolerated. I’m looking forward to reading more than just the abstract tho (confession).

Martin - thanks for all your cool work!

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#5
I recently finished a 2nd reading of DDIA and while listening to a podcast featuring an interview with Martin Kleppmann, I got so thrilled when he mentioned that he plans to release another book in the coming years.

DDIA is so good that I feel the same kind of anticipation I have as when waiting for a next in a series fantasy book to take me back to a parallel world with characters I've come to love and miss like one misses a good friend they haven't seen for a while.

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#6
post #5

I recently finished a 2nd reading of DDIA and while listening to a podcast featuring an interview with Martin Kleppmann, I got so thrilled when he mentioned that he plans to release another book in the coming years. DDIA is so good that I feel the same kind of anticipation I have as when waiting for a next in a series fantasy book to take me back to a parallel world with characters I've come to love and miss like one…

Which podcast?

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#7
> The 3f + 1 assumption means these protocols cannot be deployed in open peer-to-peer systems, since they would be vulnerable to Sybil attacks. In contrast, my approach makes no assumption about the number of Byzantine nodes.

I'm confused - probably because I haven't finished reading the paper.

1. Sybil-proof-ness requires a CA [1]. It's orthogonal to whether or not a protocol is BFT. Specifically, the classical BFT protocols "assume" there exist a CA, and then prove their protocols to be BFT.

2. I won't comment whether 3f+1 protocols cannot be deployed in open P2P systems (they can), but "makes no assumption about the number of Byzantine nodes" is weird. This result is valid in a particular system/time model eg. With PKI, in synchronous setting, for any `f` one can achieve consensus in `f+1` rounds using Dolev-Strong. This means you make no assumption about `n`, but the protocol is impractical for variety of reasons eg. large `n`, strong synchrony etc.

[1] https://www.microsoft.com/en-us/research/wp-content/uploads/...

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#8
post #5

I recently finished a 2nd reading of DDIA and while listening to a podcast featuring an interview with Martin Kleppmann, I got so thrilled when he mentioned that he plans to release another book in the coming years. DDIA is so good that I feel the same kind of anticipation I have as when waiting for a next in a series fantasy book to take me back to a parallel world with characters I've come to love and miss like one…

DDIA = Designing Data Intensive Applications

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#9
post #7

> The 3f + 1 assumption means these protocols cannot be deployed in open peer-to-peer systems, since they would be vulnerable to Sybil attacks. In contrast, my approach makes no assumption about the number of Byzantine nodes. I'm confused - probably because I haven't finished reading the paper. 1. Sybil-proof-ness requires a CA [1]. It's orthogonal to whether or not a protocol is BFT. Specifically, the classical BFT…

The big novel feature in Nakamoto consensus (the Bitcoin paper one) is precisely that it gives you Sybil-proof BFT without a CA. That's the whole reason for the massive energy consumption.

Re: Making CRDTs Byzantine Fault Tolerant [pdf]

#10
post #9
post #7

> The 3f + 1 assumption means these protocols cannot be deployed in open peer-to-peer systems, since they would be vulnerable to Sybil attacks. In contrast, my approach makes no assumption about the number of Byzantine nodes. I'm confused - probably because I haven't finished reading the paper. 1. Sybil-proof-ness requires a CA [1]. It's orthogonal to whether or not a protocol is BFT. Specifically, the classical BFT…

The big novel feature in Nakamoto consensus (the Bitcoin paper one) is precisely that it gives you Sybil-proof BFT without a CA. That's the whole reason for the massive energy consumption.

It doesn't give you sybil-proof. It gives you sybil-resistance, and that, in a non-deterministic protocol.
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