[BOUNTY] A patch for bitcoind to modify tx list in "getmemorypool"

[DeathAndTaxes]

That wouldn't allow miners to change fees quickly. IMO, a better solution is to push a URI and signing pubkeyhash into the coinbase... then have a simple (signed) script at the URI that calculates the fee required for a given txn.

Interesting. Or possibly just a signed fee manifest at the URI.   Client detects new block, checks coinbase for tx fee data and uses uri to grab fee manifest.  Client updates its database.

Alternatively if blocks are signed (which is useful in other applications) with pubkeyhash a miner could simply transmit an updated fee manifest (via a new message type) to the network as needed.  each node would check to validate manifest and relay only if valid.  some sort of spam rule would be needed to avoid a DOS.    Still the combination of node being able to sign the block (proof of hashing power) and publish a fee manifest gives clients the ability to compute time vs fee effectively.

Anyways this is why it is useful to start the discussion.

[1715201784]

1715201784

[1715201784]

1715201784

[marked]

That wouldn't allow miners to change fees quickly. IMO, a better solution is to push a URI and signing pubkeyhash into the coinbase... then have a simple (signed) script at the URI that calculates the fee required for a given txn.

"n" could be one block, or are you suggesting that miners would need to vary within a single block?

EDIT: I suggested that the client generate the fee from a message as it might be possible for the miner to be down/DDoSd, and another miner could/would pick up the txn.

Are there use cases where a script at a URI would be an issue due to latency? I'm thinking of fast txns over slow/satellite links, but can't honestly think of a current use case for that scenario (the bitcoin cash terminal is the only one I can think of that may be relevant).


marked

[Polvos]

One related question.  Is it possible to have bitcoind create a tx but not broadcast it?  If so is it then part of the memorypool?  If not could bitcoind be modified to make it part of the memorypool?  Essentially I want the ability to include a tx in a block that hasn't been broadcasted (coin melting).

YU-HUUUU

Let's melt some coins and hearts.

[Polvos]

Polvos, you also offered to contribute toward the bounty; if you feel the desire to tip me, you can use 1DGzpZzce1c7nsg1SN7exV6bsaju1Mcrc6 - it's fine with me if you choose not to, though.

Nice work, coder. Tipped you 5 BTC. Please, can you think a little about the melt mining work? I think it's good to counter MtGox abuse. Thank you.

[DeathAndTaxes]

Examples usage of setminfee

Setting minfee of 0.005 BTC per KB

Code:

E:\bitcoin\bitcoin-0.6.0rc5+customfee-win32>bitcoind setminfee 0.0005
true

Checking minfee using getmininginfo

Code:

E:\bitcoin\bitcoin-0.6.0rc5+customfee-win32>bitcoind getmininginfo
{
    "blocks" : 173278,
    "currentblocksize" : 1000,
    "currentblocktx" : 0,
    "difficulty" : 1498294.36281651,
    "errors" : "",
    "generate" : false,
    "genproclimit" : -1,
    "hashespersec" : 0,
    "pooledtx" : 37,
    "minfee" : 0.00050000,
    "minfeeper" : 1000,
    "testnet" : false
}

Checking the memorypool returned by bitcoind (used by p2pool or solominer to generate work)

Code:

E:\bitcoin\bitcoin-0.6.0rc5+customfee-win32>bitcoind getmemorypool
{
    "version" : 1,
    "previousblockhash" : "0000000000000223a54ba1689d09a07aac9c172002fee5866b18c
2e52ecf5569",
    "transactions" : [
    ],
    "coinbasevalue" : 5000000000,
    "coinbaseflags" : "062f503253482f",
    "time" : 1332941298,
    "mintime" : 1332936934,
    "curtime" : 1332941298,
    "bits" : "1a0b3287"
}

Note tx section is empty.  At the time of execution the node has not received any unconfirmed tx with a fee of >= 0.0005 BTC


Setting the minfee to 1 satoshi (1E-8 BTC, the smallest unit in Bitcoin) and checking mempool
Essentially this includes all paying txs and excludes all non-paying txs.

Code:

E:\bitcoin\bitcoin-0.6.0rc5+customfee-win32>bitcoind setminfee 0.00000001
true

E:\bitcoin\bitcoin-0.6.0rc5+customfee-win32>bitcoind getmemorypool
{
    "version" : 1,
    "previousblockhash" : "000000000000087818d53138fbd4256625e37c98a38b6fe8569e56852c92ab70",
    "transactions" : [
        "0100000004820c6bd1fa106889710348767abb456e5f38b82c3acf570a3c2635480bab6761010000008c493046022100f3cd34b9f81b525
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7f31012aac52affffffff0249a5a700000000001976a914b31e6898ceb2fe42ab62ee03400ac24cab90be0f88ac00ca9a3b000000001976a914abe03
f415de01d078829249d0abdec8c61466aab88ac00000000",
        "0100000001595e7ee07f3d6036f2e28c290e4e5cab0689fc5153217fff0e43e95118862c61000000008b483045022100a2d355c1a460b4f
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3d56b1ae91f9f908ef5a485f12612d1b788ac00000000",
        "0100000008986745fd96b4112c018e1cdecfe7f51008026f19822856bee9dbd789192d8b732a0000008b483045022100fa5fa977579fc60
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7565eedfeeb95ffffffff708c77f212d0f70535aa1ab2a08d45499469d4c5b8c969166d18921e4c7ce36a360000008b4830450221009d41e4dc8095b
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7565eedfeeb95ffffffff72d37e5d931dd8c379052d702afb25983927055dd4a621aac66901a13bba6a9d2f0000008a47304402206b20c438e2a981c
82385eca99ac00d17bf3893c0b23092a3da9be747347edf4702201712aa42ff4bf37d64298c477b34061713989677c9fe4df0f619331025bcce62014
10414bf0a8673732d34c20aee6c790a563d4025278ae510ff2ff4e0e2098bd65cd892ec596a7335fb250ecf70dd54a1351214301da2b69bfad4d5f75
65eedfeeb95ffffffff80b290fc21ad8b97521fb67961a5983361ce053ba9959ab2188258857edbc215180000008b48304502210085c56958bafe3e8
32aadc2a354f2de76467b60e653a47b964c7eddb0f7344dda0220084d691b196acbbf33d94aec64d044f10f95f5050e58b00fb3309d72d41e3564014
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65eedfeeb95ffffffff1053469ea8e4e643fff50eabe8ed92d0c877a4ca7497151304578fdba730425e750000008c493046022100a682b3cfd7aa01c
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7565eedfeeb95ffffffff682397d21cf100e2e37819a25ddc9421bd35aab8aacbfb77e33ea2e50ded4079130000008c49304602210082767c02c33ee
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5f7565eedfeeb95fffffffff3326d4c5c34b116c4af6672e46ac09dabdb039a22e5cc249a2810a343328c343e0000008b4830450220395aa223d95ee
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5f7565eedfeeb95ffffffff0266dc0200000000001976a914f52562ac702bd680e224adced83c83a18db7cead88ac400d380c000000001976a914bbc
dec3fc1e60e61815ce3017ef4628715f995bb88ac00000000",
        "010000000199ea376b2eff833fc3e28beceaec19943b241d82803e5628ae15a5332fc016211e0000008c493046022100adf90d9a6875f81
da1777ec4bd3d4c243851807250bbba2a546afcd52c25f39e022100dbea922df2ee0297bc2fd4b336526f92fbb19e5341ada461188599f10e61e58f0
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57058bcf8c16cffffffff02a29d0000000000001976a9148c5cfffd4b8b2b5c7491fd8f8bf29078edb9f18f88ac60198501000000001976a91411574
6a81d18e3142141facf9e0e34326c25831e88ac00000000",
        "0100000001ded223b8ea4f7ba4586db2e6cf975719e7bd5d36febdabe8629b1c532e978d9a010000006c493046022100ef2467f2c8e806b
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12102cce9c77c9586f5ba9cf8682a200522b235f0aa3e46c681e7698f1867a47c071fffffffff0220a10700000000001976a914c9eb4dd2f5175a15f
b11a638450dba76396569be88ace02f3808000000001976a9142dbde30815faee5bf221d6688ebad7e12f7b2b1a88ac00000000",
        "01000000017703b5bdddfcff918bd2502d13a37fcc41d3741711ba4ceb83a8d05bcb9b6b21010000006b483045022100cfceae940568471
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102cce9c77c9586f5ba9cf8682a200522b235f0aa3e46c681e7698f1867a47c071fffffffff0220a10700000000001976a914b0af94b8add7c589747
ebf5c8be217cf04fff1d888ac50ea1a05000000001976a9142dbde30815faee5bf221d6688ebad7e12f7b2b1a88ac00000000",
        "01000000013e4ddad8766a7d899d60deeb958da585247c801dbfbaa6cb969f645e8cac40c8000000008b483045022100a6a031ab842b8b8
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c9deba304b7773cd5a7de0d55a739852988ac00000000",
        "0100000001e908118907b83ad6db5250271070c7253971a2c3b7a47a283953a4640096bc4d000000008c493046022100985506639078d54
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ecf89e7b13082b9e90a1a8c62115465bd3b88ac00000000",
        "01000000011ab8482a97a10f046513944e1425e601a296920d469184c8ad937c31043078e0000000008b48304502206f0480265d67e0f0a
7084610f545439b1c35cf1f98e6181d932d1db1238fc2380221008c302b27c3ba22c478dec3feb0fb7c1235be615afa627641a0bfc7ac9d939dfd014
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7da92eed571ffffffff02a04da206000000001976a914cee251fb299a547d29e2d3f8c0475f8c3a8b793688acc0d8a700000000001976a914c347c45
81999a0f2875aa9ddbee9e47236b291e788ac00000000",
        "01000000019032628f653fba3273c0124294ec60567c675c35866326b235fbe9bb0179c370000000008a473044022075a988ab396170d17
9872320ad663ca41bd12b1ca5db007ada82e178f9508d4502200c03e286231346e3e5f2cbb4728265d8fd748d74df637a1edd3a32eba0885cf001410
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1c49d711dffffffff0230a21306000000001976a914539fde3640b31e49096aaab08907461c59e7740988ac20e88d00000000001976a91423d5b12c9
deba304b7773cd5a7de0d55a739852988ac00000000"
    ],
    "coinbasevalue" : 5001450000,
    "coinbaseflags" : "062f503253482f",
    "time" : 1332941492,
    "mintime" : 1332938361,
    "curtime" : 1332941492,
    "bits" : "1a0b3287"
}

Roughly 10% of tx volume includes a fee of some token amount.

p2pool works fine with modified bitcoind.  I have noticed no errors, changes in payout, increase in stales, or reduction reported hashpower.

[dooglus]

One related question.  Is it possible to have bitcoind create a tx but not broadcast it?  If so is it then part of the memorypool?  If not could bitcoind be modified to make it part of the memorypool?  Essentially I want the ability to include a tx in a block that hasn't been broadcasted (coin melting).

A problem with this would be what to do if you create one of these 'melt' transactions, but don't manage to mine a block before shutting down bitcoind.  The transaction is stored in the wallet along with any other pending transactions.  The wallet format doesn't currently store whether a transaction is "secret" or not.  It could do, but that would make the wallet format incompatible with standard client wallet files.

A simple solution would be for the client never to broadcast any transactions that you create on the client while in the new mode.  The wallet already has a field for each transaction which says whether you created it or not.  Another would be to have a threshold, and never broadcast any of your transactions which have a fee over a certain amount.

Given this, do you have any further thoughts on how you want this feature to work?

[DeepBit]

One related question.  Is it possible to have bitcoind create a tx but not broadcast it?  If so is it then part of the memorypool?  If not could bitcoind be modified to make it part of the memorypool?  Essentially I want the ability to include a tx in a block that hasn't been broadcasted (coin melting).

Yes, it's possible, but not secure enough.

1. If your block becomes orphaned, someone will pick this TX and take fees.
2. Big miners can cooperate and intentionally invalidate blocks with unusually high fees to pick them up and split profits.

Otherwise the idea is good.

[dooglus]

Yes, it's possible, but not secure enough.

1. If your block becomes orphaned, someone will pick this TX and take fees.
2. Big miners can cooperate and intentionally invalidate blocks with unusually high fees to pick them up and split profits.

Otherwise the idea is good.

Good points.  Guess there's no point implementing it then...

[Polvos]

Yes, it's possible, but not secure enough.

1. If your block becomes orphaned, someone will pick this TX and take fees.
2. Big miners can cooperate and intentionally invalidate blocks with unusually high fees to pick them up and split profits.

Otherwise the idea is good.

And what's the difference between this big miners cooperation an the cooperation needed for a 51 % attack?

[dooglus]

Yes, it's possible, but not secure enough.

1. If your block becomes orphaned, someone will pick this TX and take fees.
2. Big miners can cooperate and intentionally invalidate blocks with unusually high fees to pick them up and split profits.

Otherwise the idea is good.

And what's the difference between this big miners cooperation an the cooperation needed for a 51 % attack?

None.  But point 1 doesn't need cooperation at all.

[Polvos]

But if I'm not wrong the % of orphan blocks is very low

[DeepBit]

Yes, it's possible, but not secure enough.

1. If your block becomes orphaned, someone will pick this TX and take fees.
2. Big miners can cooperate and intentionally invalidate blocks with unusually high fees to pick them up and split profits.

Otherwise the idea is good.

And what's the difference between this big miners cooperation an the cooperation needed for a 51 % attack?

"Simple" 51% attack doesn't allows them to redeem your TXes, but with "coin melting" it becomes possible. And it looks a bit less evil (just kidding).

[Berlu]

What's the benefit of "coin melting"?
If you just want to merge multiple "junk" inputs to one output, why do you add any tx fee at all?

[dooglus]

What's the benefit of "coin melting"?
If you just want to merge multiple "junk" inputs to one output, why do you add any tx fee at all?

I imagine you only use 'coin melting' if the accepted method of calculating which coins are 'tainted' only looks at inputs and outputs, and ignores transaction fees.

If coin melting ever becomes popular then it will stop being effective, as the taint calculations start taking it into account.

[DeathAndTaxes]

What's the benefit of "coin melting"?
If you just want to merge multiple "junk" inputs to one output, why do you add any tx fee at all?

I imagine you only use 'coin melting' if the accepted method of calculating which coins are 'tainted' only looks at inputs and outputs, and ignores transaction fees.

If coin melting ever becomes popular then it will stop being effective, as the taint calculations start taking it into account.

Unlikely unless you want to bankrupt miners by considering their block rewards tainted.

[btharper]

What's the benefit of "coin melting"?
If you just want to merge multiple "junk" inputs to one output, why do you add any tx fee at all?

I imagine you only use 'coin melting' if the accepted method of calculating which coins are 'tainted' only looks at inputs and outputs, and ignores transaction fees.

If coin melting ever becomes popular then it will stop being effective, as the taint calculations start taking it into account.

Unlikely unless you want to bankrupt miners by considering their block rewards tainted.

It may be possible to analyze based on how much fee they're giving away. If a miner accepts a 0.001 BTC tainted fee then it's taint might negligibly increase. If a miner accepts a 3 BTC tx fee with no outputs, then the coin is probably being melted.

Losses from orphaned blocks might just be part of the cost of business for this type of transaction. I could also see it as an incentive to melt slowly as well.

[dooglus]

Is this bounty still available?  It wouldn't be hard to implement if there's still interest in it.

[Luke-Jr]

Is this bounty still available?  It wouldn't be hard to implement if there's still interest in it.

I did it a long time ago. It's pretty much obsolete now, though.