[bitcoin-dev] Solving the Scalability Problem on Bitcoin

Sun Aug 27 12:10:19 UTC 2017

>>> 5) The problem with node pruning is that it is not standardized, and
for a new node to enter the network and to verify the data, it needs to
download all data and prune it by itself. This will drastically lower the
information needed by the full nodes by getting rid of the junk.  Currently
we are around 140GB, that number is getting bigger exponentially, by the
number of users and transactions created. It could reach a Terrabyte sooner
than expected, we need to act now.

To have to download all blockchain for then prune is a big drawback.
So I thought about the concept of "trusted" nodes, where you could choose
some nodes to connect and from which block you want to download. Of course
they would do this by their own risk, but there are ways to minimize the
risk, like:
  - check the latest blocks (hashes) if they match what you find in some
sites, like blockchain.info
  - download and compare the utxo from all (some) the nodes you are
connected

Currently utxo size is around 2GB and we cant know how fast it will grow (?)

Em 26/08/2017 19:39, "Adam Tamir Shem-Tov via bitcoin-dev" <
bitcoin-dev at lists.linuxfoundation.org> escreveu:

Thank you Thomas for your response.

1) Implement solution is impossible... I have given a solution in part II.
By adding a Genesis Account which will be the new sender.

2)Keeping older blocks: Yes as I said 10 older blocks should be kept, that
should suffice. I am not locked on that number, if you think there is a
reason to keep more than that, it is open to debate.

3) Why 1000? To be honest, that number came off the top of my head. These
are minor details, the concept must first be accepted, then we can work on
the minor details.

4)Finally it's not just the addresses and balance you need to save...  I
think the Idea of the Genesis Account, solves this issue.

5) The problem with node pruning is that it is not standardized, and for a
new node to enter the network and to verify the data, it needs to download
all data and prune it by itself. This will drastically lower the
information needed by the full nodes by getting rid of the junk.  Currently
we are around 140GB, that number is getting bigger exponentially, by the
number of users and transactions created. It could reach a Terrabyte sooner
than expected, we need to act now.

On your second email:
When I say account: I mean private-public key.
The way bitcoin works, as I understand it, is that the funds are verified
by showing that they have an origin, this "origin" needs to provide a
signature, otherwise the transaction won't be accepted.
If I am proposing to remove all intermediate origins, then the funds become
untraceable and hence unverifiable. To fix that, a new transaction needs to
replace old ones. A simplified version: If there was a transaction chain
A->B->C->D, and I wish to show only A->D, only a transaction like that
never actually occurred, it would be impossible to say that it did without
having A's private key, in order to sign this transaction. In order to
create this transaction, I need A's private key. And if I wish this to be
publicly implemented I need this key to be public, so that any node
creating this Exodus Block can sign with it. Hence the Genesis Account. And
yes, it is not really an account.

On 27 August 2017 at 00:31, Thomas Guyot-Sionnest <dermoth at aei.ca> wrote:

> Pruning is already implemented in the nodes... Once enabled only unspent
> inputs and most recent blocks are kept. IIRC there was also a proposal to
> include UTXO in some blocks for SPV clients to use, but that would be
> additional to the blockchain data.
>
> Implementing your solution is impossible because there is no way to
> determine authenticity of the blockchain mid way. The proof that a block
> hash leads to the genesis block is also a proof of all the work that's been
> spent on it (the years of hashing). At the very least we'd have to keep all
> blocks until a hard-coded checkpoint in the code, which also means that as
> nodes upgrades and prune more blocks older nodes will have difficulty
> syncing the blockchain.
>
> Finally it's not just the addresses and balance you need to save, but also
> each unspent output block number, tx position and script that are required
> for validation on input. That's a lot of data that you're suggesting to
> save every 1000 blocks (and why 1000?), and as said earlier it doesn't even
> guarantee you can drop older blocks. I'm not even going into the details of
> making it work (hard fork, large block sync/verification issues, possible
> attack vectors opened by this...)
>
> What is wrong with the current implementation of node pruning that you are
> trying to solve?
>
> --
> Thomas
>
> On 26/08/17 03:21 PM, Adam Tamir Shem-Tov via bitcoin-dev wrote:
>
> <B> Solving the Scalability issue for bitcoin </B> <BR>
>
> I have this idea to solve the scalability problem I wish to make public.
>
> If I am wrong I hope to be corrected, and if I am right we will all gain
> by it. <BR>
>
> Currently each block is being hashed, and in its contents are the hash of
> the block preceding it, this goes back to the genesis block.
>
> <BR>
>
> What if we decide, for example, we decide to combine and prune the
> blockchain in its entirety every 999 blocks to one block (Genesis block not
> included in count).
>
> <BR>
>
> How would this work?: Once block 1000 has been created, the network would
> be waiting for a special "pruned block", and until this block was created
> and verified, block 1001 would not be accepted by any nodes.
>
> This pruned block would prune everything from block 2 to block 1000,
> leaving only the genesis block. Blocks 2 through 1000, would be calculated,
> to create a summed up transaction of all transactions which occurred in
> these 999 blocks.
>
> <BR>
>
> And its hash pointer would be the Genesis block.
>
> This block would now be verified by the full nodes, which if accepted
> would then be willing to accept a new block (block 1001, not including the
> pruned block in the count).
>
> <BR>
>
> The new block 1001, would use as its hash pointer the pruned block as its
> reference. And the count would begin again to the next 1000. The next
> pruned block would be created, its hash pointer will be referenced to the
> Genesis Block. And so on..
>
> <BR>
>
> In this way the ledger will always be a maximum of 1000 blocks.
>
>
>

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