Re: [Bitcoin-development] NODE_BLOOM BIP
The original Bloom filtering spec did not make this feature optional for the same reason gzip isn't an optional part of the PNG specification. I see no reason to revisit that. It's definitely not the case that making every possible feature optional is smart design, often it's the opposite. If in future there are nodes that for some reason can't technically support this feature, then there'd be a stronger rationale for something like this. However no such nodes exist, nor are they likely to in future given that it's a simple feature to implement. For these reason I oppose this BIP. On Sun, Aug 18, 2013 at 4:59 AM, Peter Todd p...@petertodd.org wrote: My draft is as follows. Gregory Maxwell: Can you assign a BIP # for this? The next number, 38, is on the wiki as Passphrase-protected private key by Mike Caldwell, although it isn't in the list so I don't know if that is official or not. BIP: ? Title: NODE_BLOOM service bit Author: Peter Todd p...@petertodd.org Type: Standards Track (draft) Created: 17-08-2013 Abstract This BIP extends BIP 37, Connection Bloom filtering, by defining a service bit to allow peers to advertise that they support bloom filters explicitly. Motivation == BIP 37 did not specify a service bit for the bloom filter service, thus implicitly assuming that all nodes that serve peers data support it. There are however cases where a node may want to provide data, such as mempool transactions and blocks, but do not want to or have not implemented bloom filtering. Additionally it is good practice for nodes to be given options as to the granularity of the services they are providing the public - a full-node operator may be able to donate only a small amount of bandwidth and may want those efforts to be used by other full-node operators. Specification = The following protocol bit is added: NODE_BLOOM = (1 1) In addition the protocol version is increased from 70001 to 70002 in the reference implementation. Nodes that support bloom filters should set that protocol bit. Otherwise it should remain unset. NODE_BLOOM is distinct from NODE_NETWORK, and it is legal to advertise NODE_BLOOM but not NODE_NETWORK. If a node does not support bloom filters but receives a filterload, filteradd, or filterclear message from a peer the node should disconnect that peer immediately. While outside the scope of this BIP it is suggested that DNS seeds and other peer discovery mechanisms support the ability to specify the services required; current implementations simply check only that NODE_NETWORK is set. Design rational === A service bit was chosen as applying a bloom filter is a service. The increase in protocol version is for backwards compatibility. Nodes that require the bloom filter service can set NODE_BLOOM for peers advertising a protocol version 70002, allowing the rest of the implementation to be unchanged. Nodes with implementations that do not know of the NODE_BLOOM bit will be disconnected immediately as though the connection failed for some reason, and thus will not have incoming bandwidth wasted by that peer and can easily connect to another peer. Supporting NODE_BLOOM but not NODE_NETWORK allows for situations where a node may have data that its peers may be interested in, but is not a full node and thus does not have block data in general. For instance an SPV node that receives a full, unfiltered, block from a peer may want to let its SPV peers know about the existence of that block and provide them that data if requested. Those peers in turn may only be interested in knowing about the block if it matches a specific bloom filter. Note how in this example DoS attacks are made prohibitively expensive by the work required to create a valid block header. Reference Implementation https://github.com/bitcoin/bitcoin/pull/2900 Copyright = This document is placed in the public domain. -- 'peter'[:-1]@petertodd.org -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in
Re: [Bitcoin-development] NODE_BLOOM BIP
Mike pointed out exactly the reason I oppose a NODE_BLOOM service bit: I also think it is a bad idea to start making various bits and pieces of the protocol optional. It is bad for privacy (easier to fingerprint nodes) and bad for decentralization (fewer nodes support your required feature set). And every bit you add can give you an exponential number of combinations your QA team should test. I'd say the same thing about NODE_TRANSACTION (I don't know about blocks, have and NODE_BLOCK bits. -- -- Gavin Andresen -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] NODE_BLOOM BIP
On Mon, Aug 19, 2013 at 12:00:23AM +0200, Mike Hearn wrote: The original Bloom filtering spec did not make this feature optional for the same reason gzip isn't an optional part of the PNG specification. I see no reason to revisit that. It's definitely not the case that making every possible feature optional is smart design, often it's the opposite. Bloom filtering isn't lossless so to speak. A better analogy would be making re-sharing an optinal part of the BitTorrent specification, and then expecting that the majority of users would never upload data to peers that needed it. -- 'peter'[:-1]@petertodd.org signature.asc Description: Digital signature -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Gavin's post-0.9 TODO list...
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 On Fri, Aug 16, 2013 at 2:15 PM, Peter Todd p...@petertodd.org wrote: On Fri, Aug 16, 2013 at 10:01:16AM -0400, Peter Todd wrote: Doing this also makes it more difficult to sybil the network - for instance right now you can create SPV honeypots that allow incoming connections only from SPV nodes, thus attracting a disproportionate % of the total SPV population given a relatively small number of nodes. You can then use that to harm SPV nodes by, for instance, making a % of transactions be dropped deterministicly, either by the bloom matching code, or when sent. Users unlucky enough to be surrounded by sybil nodes will have their transactions mysteriously fail to arrive in their wallets, or have their transactions mysteriously never confirm. Given how few full nodes there are, it probably won't take very many honeypots to pull off this attack, especially if you combine it with a simultaneous max connections or bloom io attack to degrade the capacity of honest nodes. Oh, here's an even better way to do the tx drop attack: when you drop a transaction, make a fake one that pays the same scriptPubKeys with the same amount, and send it to the SPV peer instead. They'll see the transaction go through and show up in their wallet, but it'll look like it got stuck and never confirmed. They'll soon wind up with a wallet full of useless transactions, effectively locking them out of their money. Excellent, and makes a mockery of zero-confirmation transactions to boot. Can be prevented by passing along txin proofs, but they require the full transaction, so the effective UTXO set size would go up greatly post-pruning. I am sure Mike would love to demand that full nodes do this for their peers though, at least until UTXO commitments are greated, at great cost to full nodes. On the other hand, a tx with some txin proofs can be safely relayed by SPV nodes, an interesting concept. Do the UTXO commitment people have keeping proof size small in mind? Here's another question for you Mike: So does bitcoinj have any protections against peers flooding you with useless garbage? It'd be easy to rack up a user's data bill for instance by just creating junk unconfirmed transactions matching the bloom filter. That is good too. I'll bounty 2.5BTC to implement the first attack, and 0.5BTC for the second. Should be easy to do as a patch to satoshi bitcoin I think. The implementation must include a RFC3514 compliant service bit to let peers know of the operators intentions. Along those lines I'll donate 3BTC to adding service bit selection to DNS seeds. We should clearly show people the limitations of SPV before they depend too much on it. Nothing wakes users up like a 21 million BTC transaction in their wallet. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBCAAGBQJSEYvxAAoJEEWCsU4mNhiPxI8IAJaWJ9s0YG3Ex5h8Dr6oPJ9M uXTXa/Rt0DqS6mmyD9O80sXfgPbPbQa2rDL6imlqONaWfpXFZl2W9vxRGaZJ9wrr 3KBHzK8lasDOKqlEX92h8ZmQBjw4w5bK/heRLo1PnSZ8ojKn8+My1JvZWOPzF0Ct tDXXuCE94csKuGRdmdDdVoXqy4XZaMQhHrGbrWVotQs1HzX3iK146GoGaZC0YyBx cdWg/xDPtAxgb5zf2RSeNHfXeY0wZawe8vBxaS56gCRl54PG7fJvqL+YPcarNb1p zEmahJjoyQHskjFeDpgEiXnWu3K3JGTSA5GvekWvBbJCcV4o1E6EI6LG0f1SfIs= =12DC -END PGP SIGNATURE- -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Gavin's post-0.9 TODO list...
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