Download blockchain

[ICOs]

How to download blockchain all at once? Is there any site where I can download an updated copy of the blockchain?

[HCP]

That defeats the purpose of the blockchain.

The value of the blockchain is that it is immutable and can be verified from the beginning to the end as each block references the previous block. By simply downloading all of the data, you are skipping the block validation which could potentially open yourself up to issues if the data is "bad".

Additionally, it means you need to fully trust the source of the data... which also goes against the whole "Trustless" system that Bitcoin is designed for.

Finally, given the recent updates, it is also faster and more efficient to simply sync the full blockchain using the Bitcoin Core client than it is to use a "bootstrap" anyway...

[btcton]

There used to be a torrent version of the blockchain that had most of the blocks up until a certain point at which the torrent was created. It basically worked as an archive of the blockchain so that people could download it that way and then start up Bitcoin Core to download only the most recent blocks that were mined after the torrent creation. I am not sure if anything like this is still being done, as I believe it is actually faster than using Bitcoin Core itself (contrary to what the poster before me claims). Unless there was a change to the peering system in the Bitcoin Core desktop application, this would be the fastest way to download the blockchain. Given how big it has gotten, however, I would not be surprised if the effort to do this was stopped. I recommend that you benchmark your speeds with Bitcoin Core and only really use the torrent (if you can find it) if you feel that it is too small. I have not run a full node myself in a while, so I cannot atest to any changes that might have happened since then.

[HCP]

The original thread regarding the bootstrap download is here: https://bitcointalk.org/index.php?topic=145386.0 It hasn't been updated since August 2014. There is a reason they stopped making/updating the "bootstrap.dat" torrent and offering it for download... since v0.10 optimisations have made it slower to use than just letting Core sync naturally.

IMPORTANT NOTE:  As of Bitcoin Core version 0.10.0 or later, this torrent is slower than a direct download using the bitcoin P2P protocol & client.  This torrent is now only maintained for research and development purposes as a secondary option.  Please use Bitcoin Core directly to download the blockchain.

And of course, there were more optimisations in v0.15(.0.1) to make it even faster: https://bitcoin.org/en/release/v0.15.0.1#performance-improvements

[ICOs]

The original thread regarding the bootstrap download is here: https://bitcointalk.org/index.php?topic=145386.0 It hasn't been updated since August 2014. There is a reason they stopped making/updating the "bootstrap.dat" torrent and offering it for download... since v0.10 optimisations have made it slower to use than just letting Core sync naturally.

IMPORTANT NOTE:  As of Bitcoin Core version 0.10.0 or later, this torrent is slower than a direct download using the bitcoin P2P protocol & client.  This torrent is now only maintained for research and development purposes as a secondary option.  Please use Bitcoin Core directly to download the blockchain.

And of course, there were more optimisations in v0.15(.0.1) to make it even faster: https://bitcoin.org/en/release/v0.15.0.1#performance-improvements

Thanks. Didn't know the client had been updated to make this faster.

[sunk818]

It is not faster for me. Taking too many hours to process the transactions. I'm still at Oct 2015 after 24 hours. I rather download a bootstrap.dat ... I thought all the transactions had to be verified even if you download a bootstrap.dat. How can there be corruption of data if you require consensus from 51% of peers? Its all old confirmed transactions anyway...

[achow101]

It is not faster for me. Taking too many hours to process the transactions. I'm still at Oct 2015 after 24 hours. I rather download a bootstrap.dat ... I thought all the transactions had to be verified even if you download a bootstrap.dat.

Using the bootstrap.dat is slower because you have to download then verify all of the blocks after the download. It is faster to let it sync normally because you are downloading and verifying blocks at the same time.

How can there be corruption of data if you require consensus from 51% of peers? Its all old confirmed transactions anyway...

That's not at all how Bitcoin works. Anyone can just give you data; it's not like the bootstrap.dat is some magic file that can't be altered. Your node still must verify that the blocks provided are correct. 51% of nodes has nothing to do with that.

[sunk818]

That's not at all how Bitcoin works. Anyone can just give you data; it's not like the bootstrap.dat is some magic file that can't be altered. Your node still must verify that the blocks provided are correct.

I'm sorry maybe I don't understand. If I download a bootstrap.dat - you're saying the file can be altered. Wouldn't the rest of the Bitcoin network reject the corrupted transactions? Please explain what the real-world implication and danger is in using a bootstrap.dat from a third party.

[achow101]

I'm sorry maybe I understand. If I download a bootstrap.dat - you're saying the file can be altered. Wouldn't the rest of the Bitcoin network reject the corrupted transactions? Please explain what the real-world implication and danger is in using a bootstrap.dat from a third party.

The rest of the network does not know nor does it care what data you have in your bootstrap.dat file. It isn't a file that nodes create and give to other nodes; it's a file created by humans and given to other humans.

An altered bootstrap.dat file is an attack on you, and whoever else has that file. It is not an attack on the network. At the very least, it could result in you having a completely different blockchain and then having to download the blockchain again from your peers when your node realizes that that chain it has has less work than the chain that other nodes have.

[sunk818]

I'm sorry maybe I understand. If I download a bootstrap.dat - you're saying the file can be altered. Wouldn't the rest of the Bitcoin network reject the corrupted transactions? Please explain what the real-world implication and danger is in using a bootstrap.dat from a third party.

The rest of the network does not know nor does it care what data you have in your bootstrap.dat file. It isn't a file that nodes create and give to other nodes; it's a file created by humans and given to other humans.

An altered bootstrap.dat file is an attack on you, and whoever else has that file. It is not an attack on the network. At the very least, it could result in you having a completely different blockchain and then having to download the blockchain again from your peers when your node realizes that that chain it has has less work than the chain that other nodes have.

It sounds like worst case I just have to download the blockchain from my peers. I'm willing to deal with that risk. It sounds like a delay and inconvenience... nothing related to financial hijacking or loss of bitcoins.