📅 Original date posted:2017-12-18
📝 Original message:Hi Greg,
2017-12-18 21:42 GMT+01:00 Gregory Maxwell <greg at xiph.org>:
> Because it would make no meaningful difference now,
Sure.
> and if you are not
> going to check the history
I'm not going to do any less checks than a node running with assumevalid.
Well not exactly true, because a node running today with assumevalid will
verify the witness root hash, right?
> there are much more efficient things to
> do-- like not transfer it at all.
>
I'm not sure what you are referring to.
Thank you
/Kalle
>
> On Mon, Dec 18, 2017 at 8:32 AM, Kalle Rosenbaum via bitcoin-dev
> <bitcoin-dev at lists.linuxfoundation.org> wrote:
> > Dear list,
> >
> > I find it hard to understand why a full node that does initial block
> > download also must download witnesses if they are going to skip
> > verification anyway. If my full node skips signature verification for
> > blocks earlier than X, it seems the reasons for downloading the
> > witnesses for those blocks are:
> >
> > * to be able to send witnesses to other nodes.
> >
> > * to verify the witness root hash of the blocks
> >
> > I suppose that it's important to verify the witness root hash because
> > a bad peer may send me invalid witnesses during initial block
> > download, and if I don't verify that the witness root hash actually
> > commits to them, I will get banned by peers requesting the blocks from
> > me because I send them garbage.
> >
> > So both the reasons above (there may be more that I don't know about)
> > are actually the same reason: To be able to send witnesses to others
> > without getting banned.
> >
> > What if a node could chose not to download witnesses and thus chose to
> > send only witnessless blocks to peers. Let's call these nodes
> > witnessless nodes. Note that witnessless nodes are only witnessless
> > for blocks up to X. Everything after X is fully verified.
> >
> > Witnessless nodes would be able to sync faster because it needs to
> > download less data to calculate their UTXO set. They would therefore
> > more quickly be able to provide full service to SPV wallets and its
> > local wallets as well as serving blocks to other witnessless nodes
> > with same or higher assumevalid block. For witnessless nodes with
> > lower assumevalid they can serve at least some blocks. It could also
> > serve blocks to non-segwit nodes.
> >
> > Do witnessless nodes risk dividing the network in two parts, one
> > witnessless and one with full nodes, with few connections between the
> > parts?
> >
> > So basically, what are the reasons not to implement witnessless
> > nodes?
> >
> > Thank you,
> > /Kalle
> >
> > _______________________________________________
> > bitcoin-dev mailing list
> > bitcoin-dev at lists.linuxfoundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> >
>
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Kalle Rosenbaum [ARCHIVE] /
npub1uw…55zf7
2023-06-07 18:08:50
in reply to nevent1q…6z3k
Author Public Key
npub1uwweecasakwtk96j3vjmkjenhnhyv4rku382txq0kmexjwuh4w2st55zf7Published at
2023-06-07 18:08:50Event JSON
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"content": "📅 Original date posted:2017-12-18\n📝 Original message:Hi Greg,\n\n2017-12-18 21:42 GMT+01:00 Gregory Maxwell \u003cgreg at xiph.org\u003e:\n\n\u003e Because it would make no meaningful difference now,\n\n\nSure.\n\n\n\u003e and if you are not\n\u003e going to check the history\n\n\nI'm not going to do any less checks than a node running with assumevalid.\nWell not exactly true, because a node running today with assumevalid will\nverify the witness root hash, right?\n\n\n\u003e there are much more efficient things to\n\u003e do-- like not transfer it at all.\n\u003e\n\nI'm not sure what you are referring to.\n\nThank you\n/Kalle\n\n\n\u003e\n\u003e On Mon, Dec 18, 2017 at 8:32 AM, Kalle Rosenbaum via bitcoin-dev\n\u003e \u003cbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\u003e \u003e Dear list,\n\u003e \u003e\n\u003e \u003e I find it hard to understand why a full node that does initial block\n\u003e \u003e download also must download witnesses if they are going to skip\n\u003e \u003e verification anyway. If my full node skips signature verification for\n\u003e \u003e blocks earlier than X, it seems the reasons for downloading the\n\u003e \u003e witnesses for those blocks are:\n\u003e \u003e\n\u003e \u003e * to be able to send witnesses to other nodes.\n\u003e \u003e\n\u003e \u003e * to verify the witness root hash of the blocks\n\u003e \u003e\n\u003e \u003e I suppose that it's important to verify the witness root hash because\n\u003e \u003e a bad peer may send me invalid witnesses during initial block\n\u003e \u003e download, and if I don't verify that the witness root hash actually\n\u003e \u003e commits to them, I will get banned by peers requesting the blocks from\n\u003e \u003e me because I send them garbage.\n\u003e \u003e\n\u003e \u003e So both the reasons above (there may be more that I don't know about)\n\u003e \u003e are actually the same reason: To be able to send witnesses to others\n\u003e \u003e without getting banned.\n\u003e \u003e\n\u003e \u003e What if a node could chose not to download witnesses and thus chose to\n\u003e \u003e send only witnessless blocks to peers. Let's call these nodes\n\u003e \u003e witnessless nodes. Note that witnessless nodes are only witnessless\n\u003e \u003e for blocks up to X. Everything after X is fully verified.\n\u003e \u003e\n\u003e \u003e Witnessless nodes would be able to sync faster because it needs to\n\u003e \u003e download less data to calculate their UTXO set. They would therefore\n\u003e \u003e more quickly be able to provide full service to SPV wallets and its\n\u003e \u003e local wallets as well as serving blocks to other witnessless nodes\n\u003e \u003e with same or higher assumevalid block. For witnessless nodes with\n\u003e \u003e lower assumevalid they can serve at least some blocks. It could also\n\u003e \u003e serve blocks to non-segwit nodes.\n\u003e \u003e\n\u003e \u003e Do witnessless nodes risk dividing the network in two parts, one\n\u003e \u003e witnessless and one with full nodes, with few connections between the\n\u003e \u003e parts?\n\u003e \u003e\n\u003e \u003e So basically, what are the reasons not to implement witnessless\n\u003e \u003e nodes?\n\u003e \u003e\n\u003e \u003e Thank you,\n\u003e \u003e /Kalle\n\u003e \u003e\n\u003e \u003e _______________________________________________\n\u003e \u003e bitcoin-dev mailing list\n\u003e \u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e \u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e \u003e\n\u003e\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20171218/f5af3a69/attachment-0001.html\u003e",
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