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Blockchains from a Distributed Computing Perspective [pdf]

cs.brown.edu

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Re: Blockchains from a Distributed Computing Perspective [pdf]

#41

Post by tromp »

bringtheaction wrote: post #35
builditand wrote: post #30

Earlier quoted context omitted.

I'm new to blockchains so I'm sorry if this is stupid, maybe somebody can explain to me. Why do everybody needs to keep everything? The chain will be much smaller with just the id and the hash of the block. The payloads could be kept only by the interested parties and could be validated when needed with the chain.

> Why do everybody needs to keep everything? Because every node in the network must be able to verify all transactions all the way from the genesis block. In order to ensure that this is possible, everyone who keeps the history must keep the full history.

With the MimbleWimble design [1] [2], inputs may be cancelled against the outputs they spend, with no loss of security. Essentially, the entire blockchain history may be collapsed to a single mega transaction, with all coinbases as inputs and the UTXO set as outputs.

[1] http://mimblewimble.cash/20160719-OriginalWhitePaper.txt

[2] https://www.youtube.com/watch?v=ovCBT1gyk9c

Re: Blockchains from a Distributed Computing Perspective [pdf]

#43

Post by mannykannot »

yarrel wrote: post #29
kang wrote: post #17

> a ledger is just an indelible, append-only log of transactions that take place between various parties. Readers should decide either the above statement is true and ethereum is not a blockchain by that definition[0] or blockchain is just an abstract buzzword. Technology wise, git is as powerful as a blockchain at being an append-only log without the most important ingredient - proof-of work. 2. There is a whole sec…

From [0] - "The transactions were not rolled back. The ETH amounts were just transferred automatically at 1,920,000 ." So a transaction did take place "between various parties", nothing previous to block 1920000 was changed, and the transfer is there for all to see.

No amount of wordplay and denial will alter the fact that the DAO fork was a de-facto rollback.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#44

Post by vertex-four »

Donzo wrote: post #37
vertex-four wrote: post #32

Earlier quoted context omitted.

So Bob tampers with them all to record “everything’s fine” all the time. What now?

Finally! He can melt all the ice-cream and destroy his customer. No, Bob's misconduct would potentially be provable in court based on the trustless data ledgers in the blockchain. Really, this example just shows one way how developers could use blockchain technology to develop applications that utilize trustless data. Imagine this same technology applied to the transfer of human organs, rather than easily replaceable…

If you have trust in a court, you don't need a trustless system, by definition.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#45

Post by winslett »

Donzo wrote: post #37
vertex-four wrote: post #32

Earlier quoted context omitted.

So Bob tampers with them all to record “everything’s fine” all the time. What now?

Finally! He can melt all the ice-cream and destroy his customer. No, Bob's misconduct would potentially be provable in court based on the trustless data ledgers in the blockchain. Really, this example just shows one way how developers could use blockchain technology to develop applications that utilize trustless data. Imagine this same technology applied to the transfer of human organs, rather than easily replaceable…

I’ve heard many scenarios like “transfer of human organs” as a scenario for blockchain, but I’m skeptical that blockchain solves problems in the tangible world all that easily. It is my perception that blockchain is great for trustless information assets, but not great for trustless tangible assets.

Blockchain can’t stop a human from stealing an organ and replacing it with a different organ. Even tracking shipping containers, which was high profile a few years ago, only requires a human to make a mistake in loading a boat to throw off the database.

In tangible-world-to-information-storage scenarios, the hard part is not the information, but the guarantee that information matches the real world. In my view, the claim that blockchain solves for a trustless tangible world is naive.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#46

Post by koheripbal »

jasonzemos wrote: post #10

You may be interested in another paper[1] by Sompolinsky and Zohar describing block-trees rather than block-chains as a better structural approach. 1: https://eprint.iacr.org/2013/881.pdf

Ethereum actually uses a reduced version of this to accept portions of competing chains so as to be more efficient.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#47

Post by drdrey »

hyperion2010 wrote: post #38
garmaine wrote: post #28

Earlier quoted context omitted.

Maybe he meant the UTXO set? Even that is off by a factor of 2 though.

Ya sorry, a bit of an exaggeration there. I was recalling the size of the hard disks that some folks routinely kept around just for storing crypto blockchains. That said, the actual numbers are already out of the rang for storage on the vast majority of commercially available mobile devices which basically relegates cryptos to enthusiasts. If we could fit a year worth of transactions in to on the order of 10 gigs, or…

The blockchain grows at a constant linear rate, 1MB every 10 min or 144MB per day. Isn't that what you mean by "constant size estimate per unit time"?

Re: Blockchains from a Distributed Computing Perspective [pdf]

#48

Post by Donzo »

winslett wrote: post #45
Donzo wrote: post #37

Earlier quoted context omitted.

Finally! He can melt all the ice-cream and destroy his customer. No, Bob's misconduct would potentially be provable in court based on the trustless data ledgers in the blockchain. Really, this example just shows one way how developers could use blockchain technology to develop applications that utilize trustless data. Imagine this same technology applied to the transfer of human organs, rather than easily replaceable…

I’ve heard many scenarios like “transfer of human organs” as a scenario for blockchain, but I’m skeptical that blockchain solves problems in the tangible world all that easily. It is my perception that blockchain is great for trustless information assets, but not great for trustless tangible assets. Blockchain can’t stop a human from stealing an organ and replacing it with a different organ. Even tracking shipping co…

It's hard to imagine a solution to these problems because we are so far away from highly functional examples of this tech in action in the "real" world.

That said, engineers live to solve problems in better, smarter ways.

I personally believe it is naive to bet against innovation in this sphere, but we both shall see if we are so fortunate.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#49

Post by Donzo »

vertex-four wrote: post #44
Donzo wrote: post #37

Earlier quoted context omitted.

Finally! He can melt all the ice-cream and destroy his customer. No, Bob's misconduct would potentially be provable in court based on the trustless data ledgers in the blockchain. Really, this example just shows one way how developers could use blockchain technology to develop applications that utilize trustless data. Imagine this same technology applied to the transfer of human organs, rather than easily replaceable…

If you have trust in a court, you don't need a trustless system, by definition.

Slippery slope: I can trust the court if I don't have to trust the data. I can't trust the court if I have to subjectively prove my arguments.
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