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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]

#31

Post by dragandj »

cdetrio wrote: post #24
kccqzy wrote: post #3

I appreciate the effort in writing this readable paper, but I do find the analogies in the first few sections to be quite strained. Here's an example: > Alice decides it is time to blockchain her supply chain. She rents some cloud storage to hold the ledger, and installs internet-enabled temperature sensors in each frozen yogurt container. She is concerned that sensors are not always reliable (and that Bob may have t…

Its easy to go through a couple containers and find/replace a few sensors. But it would be a lot of work for Bob to go through every single yogurt container and corrupt all the sensors.

Hmmm. But, how does a distributed blockchain help anyway?

Re: Blockchains from a Distributed Computing Perspective [pdf]

#32

Post by vertex-four »

Donzo wrote: post #4
kccqzy wrote: post #3

I appreciate the effort in writing this readable paper, but I do find the analogies in the first few sections to be quite strained. Here's an example: > Alice decides it is time to blockchain her supply chain. She rents some cloud storage to hold the ledger, and installs internet-enabled temperature sensors in each frozen yogurt container. She is concerned that sensors are not always reliable (and that Bob may have t…

All of the censors vote on if they have been tampered with. They will leave a record of their votes on the blockchain as Bob tampers with them in real time.

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

Re: Blockchains from a Distributed Computing Perspective [pdf]

#33

Post by masterbit »

builditand wrote: post #30
ulrikrasmussen wrote: post #18

Earlier quoted context omitted.

But that assumes that there is a trusted archival party that can verify account balances with authority. It may be technically possible to devise such a system, but as far as I understand, current decentralized blockchains require that you replay all previous transactions in order to learn the current state of the system.

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.

Look at R3 Corda, transactions only shared and stored between parties involved, not the rest of the network.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#34

Post by bringtheaction »

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…

> Technology wise, git is as powerful as a blockchain at being an append-only log without the most important ingredient - proof-of work.

PoW is not required to have a blockchain. What you need is any consensus algorithm. For example you could use Proof of Stake.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#35

Post by bringtheaction »

builditand wrote: post #30
ulrikrasmussen wrote: post #18

Earlier quoted context omitted.

But that assumes that there is a trusted archival party that can verify account balances with authority. It may be technically possible to devise such a system, but as far as I understand, current decentralized blockchains require that you replay all previous transactions in order to learn the current state of the system.

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.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#36

Post by refset »

matuszeg wrote: post #11
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

Thank you so much for this. I work in this field and have been telling my coworkers that a tree or graph would make more sense. This is what i needed. Thank you Do you know if anyone is working to implement something like this?

https://archain.org and their "Blockweave" construction sounds similar. Here is a recent talk from Code Mesh on what they're building: https://m.youtube.com/watch?v=YO3zyQvL3Yg

Re: Blockchains from a Distributed Computing Perspective [pdf]

#37

Post by Donzo »

vertex-four wrote: post #32
Donzo wrote: post #4

Earlier quoted context omitted.

All of the censors vote on if they have been tampered with. They will leave a record of their votes on the blockchain as Bob tampers with them in real time.

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 ice cream.

Challenge yourself to think of other scenarios in business where trustless data might make a difference.

Maybe you'll have a valuable idea in this wide open space.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#38

Post by hyperion2010 »

garmaine wrote: post #28
drdrey wrote: post #19

Earlier quoted context omitted.

> 1-2Tb What blockchain are you talking about? The Bitcoin blockchain is between 150 and 160 GB

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 at least provide a constant size estimate per unit time as a function of the number of transactions then we might be able to get adoption.

Re: Blockchains from a Distributed Computing Perspective [pdf]

#39

Post by [deleted] »

refset wrote: post #36
matuszeg wrote: post #11

Earlier quoted context omitted.

Thank you so much for this. I work in this field and have been telling my coworkers that a tree or graph would make more sense. This is what i needed. Thank you Do you know if anyone is working to implement something like this?

https://archain.org and their "Blockweave" construction sounds similar. Here is a recent talk from Code Mesh on what they're building: https://m.youtube.com/watch?v=YO3zyQvL3Yg

[deleted]

Re: Blockchains from a Distributed Computing Perspective [pdf]

#40

Post by garmaine »

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…

Well a full node doesn't need to keep the full block chain around, just the UTXO set. But you're not going to be able to handle the bandwidth of a full block chain on a mobile device anyway (~1TB/mo).
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