Bitcoin Forum

I would like to propose a case AGAINST the idea of shared Namecoin/Bitcoin mining.

The main reason I think Namecoin and Bitcoin should be kept apart, is perhaps to preserve the potential future value of Namecoin.  It has little to do with Bitcoin.

Merging the mining of Namecoin and Bitcoin is a bit of a marriage.  Namecoin perhaps has a better marriage candidate: Tor.

Why Tor?

Well, for one, the idea of a peer-to-peer DNS registry isn't something the world is asking for.  While recent domain name seizures have spooked many of us, they haven't really created any serious practical problems that need solving.  Very few websites are candidates to get their domain names seized, and those that are can protect themselves simply by registering themselves in other top level domains.  (This is something that they'd have to do under the Namecoin plan anyway).

On the other hand, Tor lacks a working DNS system, and forces people to use cryptic URLs to access its hidden services.  Just look at the Silk Road - their address is nonsense characters, and so they suffer from attacks like people hijacking links to them and sending people to phishing lookalikes, in the hopes that random characters XXX will look close enough to YYY that few will notice the difference.  On the other hand, if Tor had a cryptographically sound DNS system, it could offer addresses like "silkroad.onion".

The Tor project itself says about domain names (https://www.torproject.org/docs/hidden-services.html.en): that you can pick any two of the following: decentralized, secure, memorable.  And goes on to explain why enjoying all three is likely impossible, referring to "Zooko's conjecture".  Namecoin could just give the Tor project all three.  Tor project even invites it to happen: at the same link, it says: "Perhaps one day somebody will implement a Petname design for hidden service names?"

As a separate project, Namecoin has a fighting chance of actually being proposed, adopted, and integrated into the Tor infrastructure, as well as any other anonymizing project.  If it were married to the Bitcoin block chain, I just don't see how such an integration would be as attractive.

tl;dr - The world isn't demanding a .bit domain just to get access to Wikileaks when Google gets them there just fine.  Tor could really use a good DNS system, but marrying it to the Bitcoin blockchain will serve to make it unsuitable.

An extended specification for the Namecoin DNS namespace is being worked on which will include support for Tor, I2P and Freenet.

http://dot-bit.org/Domain_names

Mining BTC and NMC together strengthens the NMC network. Any bitcoin style blockchain is only as strong as it's difficulty. If you can find a method to increase the difficulty (= hash rate) this is something you should do and that increases the value of this "currency" (=block chain).

Tor has nothing to do with mining, Namecoins can still be used for what you proposed - the only difference if they can be mined at the same time with Bitcoins would be that they can be use in a more secure way.

Tell me if I'm wrong - mining BTC and NMC together creates a dependency on the BTC block chain for NMC.  If that's true, then if Tor were to include full support for NMC, then in order to cryptographically validate the NMC block chain, suddenly Tor must acquire and care about the enormous and exponentially growing Bitcoin block chain... a huge expense for a purely theoretical benefit.  Not to mention what could happen if Bitcoin makes fundamental changes to the way it works to support growth, such as pruning unneeded records off the Bitcoin block chain (which could certainly include records stuffed there for the sake of NMC).

The NMC doesn't need hash strength the same way Bitcoin does.  If NMC isn't intended for use as money, then the possibility of double spending is less of a concern and less attractive to an attacker.  The extent of disruption in the event of a >50% CPU attack would mainly concern the ability to register new names.

While I like the idea of 2 for 1 mining, I think merging the 2 projects is a mistake. The only argument I can make in favor of this merge is greed. Bitcoin is something special and starting to gain mainstream acceptance. Don't pollute the project by merging it with anything that will make an extra buck. It will most likely only destroy both projects, or at least devalue them to the point where they're basically worthless. Not to mention, what about when pussycoins come to the market, or nutsackcoins? Who decides what can/can't be merged? It's starting to make bitcoin sound a whole lot less attractive to me. Don't go down that rabbit hole.

As far as I understood it (and the wiki points out) You can mine only NMC or only BTC just fine, so you do NOT need both blockchains complete if merged mining is possible.
NMC can be double spent just like BTC - if you want a domain name, just re-mine everything since that block and claim it. One of the bigger BTC pools could even do that, considering NMC difficulty is so low.

No, you can mine NMC by itself if you desire. Plus there's no way for Tor to support Namecoin, Namecoin will support Tor instead. The Tor project doesn't have to do anything, unless by "full support" you mean buying a Namecoin domain for every hidden service that asks for one.


Namecoin is intended as a currency as well so it has the same security needs of Bitcoin.

Bitcoin is not getting polluted. You can mine BTC by itself if you don't care about mining NMC.


The miners will decide if they mergemine pussycoins or nutsackcoins depending on profitability. If nobody cares about those chains then nobody will mine them.

It is the pool who decides, not the miners... My understanding of the proposal is that this could be done by the pool without the miner's knowledge.

To take that a step further, it's the programers that would be merging the blockchains that decides... It sounds like you don't really understand what is being proposed? Sorry if I'm incorrect.

You are incorrect. What do you understand by merged mining exactly? (looks like we should have gone with the term cross mining instead of merged mining)

A chain designer can decide to make it possible to merge mine with Bitcoin, but that doesn't mean Bitcoin miners will bother merge mining with a worthless chain.

Anyway, you are not affected in any way by merged mining so I don't see what you are whining about. Actually you are affected positively, since more profitable mining will lead to more hashing power and thus better network security.

I think merging them is a mistake.  Keeping them separate will allow for more flexibility with both.   Namecoin's block chain will become secure enough as it gets used for more and more important things. 

One of the FEW drawbacks of BitCoin is the size of the block chain.  It already interferes (though I know there are workarounds) with mobile applications.   Why would you want to make it bigger? 

Merging the two block chains does not add as much value as it takes away from both projects.

From what I understand, the two block chains is not being merged together. This is the consenus by Satoshi and others long ago in the BitDNS thread.

The size of the Bitcoin blockchain is not getting bigger. Educate yourselves before giving opinions guys.

My vote is against merged mining. If a pool wants to offer a service to allow their users to mine NMC or BTC that is fine but anything where the two block chains are inter-weaved or inter-dependent or whatever-dependent word I can use is similar to pegging the Yuan to the Dollar.

I would rather namecoin grow on its own and become successful on its own without depending upon bitcoin aside from the basic principles built into the code that are alike.

The other thing I don't see is what problem(s) does merged mining solve that need to be solved for BOTH block chains? So far I don't see any problems with bitcoin's network or blockchain. I do see a need for the namecoin network to grow, but not at the reliance on bitcoin's resources, information, or anything for that matter.


After the recent revelation of the explanation of what merged mining really is. I do support it.

Then tell me how it is not getting bigger if the number of blocks in the bitcoin blockchain increases every 10 minutes or so?

Bitcoin's resources aren't being diverted. From what I understand, miners are just using the same resource against the two chains.

We are not talking about devoting half of the mining to resource to bitcoin or to namecoin.. We are talking about improving mining efficency.

Merge mining add value, rather than slicing the pie. Rather than earning bitcoins, you earn the same amount of bitcoin while also earning namecoin.

Think of your car getting an increase in fuel efficency on a single gallon of gas, rather than the gas of gallon being divided up between two cars.

Auxilliary blockchains are endless in number, the parent blockchain they look to will have more and more and more such blockchains's data in its coinbase transactions.

So it would probably be better to make a blockchain specifically for the purpose of being the parent of a potentially quite large number of auxilliary blockchains. Then bitcoin can decide whether it wants to be an auxilliary to such a thing itself or continue on its own even when possibly this metachain might become even larger in hash power than bitcoin (theoretically, as more and more chains, some possibly of some actual usefulness or value, are added to it).

-MarkM-

The chains will not be connected in any way. Merged mining will combine the power used to find hashes needed for creating blocks, regardless of which chain they belong to. Also, the value of the coins in the chains will not be linked. Namecoins will become worthless because name registration will become free, thus adding nothing new over bitcoins.


More hashing power increases security. I'd say that's a rather good thing.

Obviously I was referring to the belief that the Bitcoin chain will get bloated with Namecoin data.

That's because you don't understand the concept of merged mining that's being discussed.   ;)

This assume that there'll be an endless amount of auxiliary chains that will be worthy enough of being mined. Personally I don't even see a third chain rising to prominence in the foreseeable future. But even if so, it's ~33 bytes per block according to Mike Hearn. I could send BTC to myself once every block and I'll be adding more information than 7 auxiliary chains combined. If 33 bytes per block is a scalability problem then we are already doomed.


I don't know if I'm getting trolled or what. Read first, speak later: http://dot-bit.org/Merged_Mining

If you guys have any more objections to voice, please do so.

I am quite sure that they are probably misunderstanding.

Perhaps the real direction of "support" is on the Polipo proxy that is bundled with Tor to make browsing work.

By "full support" I mean that the client is able to cryptographically confirm the integrity of the Namecoin block chain, which it does by verifying the hashes from the genesis block to the current block.  If the Namecoin block chain is dependent on something that's being tacked onto the Bitcoin block chain, the only way it can confirm the integrity of the chain is to download both blockchains.  So, someone who wants to run a Namecoin DNS server suddenly has to download this Bitcoin block chain that will be terabytes soon and growing exponentially each time someone eats at Meze Grill or scores some weed.  All so miners can get an extra payout?

No, both chains will be independent of one another. You don't need to download the Bitcoin blockchain to "cryptographically confirm the integrity of the Namecoin block chain". You can be a regular Namecoin miner or node and still asses if a block/transaction is valid or not.

Then what's the point of sticking proof of anything in the Bitcoin block chain in the first place if nobody ever needs to read it?

If that is true, then why?

Some kind of blockchain corruption is happening. Bitcoin is desinged not to take up too much memory. Why not let the people who want to run two bitcoin clients: one for each blockchain?

I understand namecoin is in a lull right now, but that does not mean you should force bitcoin users to deal with it.

Edit: I also don't like how it is assumed that all miners are using pools.


So.. by halving how much work you do securing both block chains, you increase miner profits? If you get a successful transaction block, are both currencies included? If so, you are either leaving something insecure or bloating both blockchains.

lol @ people not understanding how things work making arguments that don't make any sense.
Protip:
1) read the alternative chains wiki page
2) understand what a merkle branch is
3) understand (2) allows securing an arbitrarily large namecoin/blahcoin block by adding ~30 bytes to a bitcoin block. 
4) understand a single bitcoin tx is more than 80bytes
5) stop whining

But then you can't use namecoin without downloading the entire bitcoin blockchain. You can't verify a specific merkle leaf without examining the whole block. Are you trying to claim that nobody will want to run a namecoin miner without the bitcoin blockchain?

Edit: what happens when bitcoin gets replaced by bictoin2, but we think namecoin is still good?

Not only can you do that, but that is in fact the entire purpose of a merkle branch.  (Note I say branch not leaf; a markle branch is a path from root to leaf, along with the siblings, so it a string of length O(log n))).
http://en.wikipedia.org/wiki/Hash_tree

So someone interested in namecoin mining/verifiction would need:

1) The bitcoin block headers
2) The namecoin blocks
3) The merkle branch from the bitcoin block header to the hash of the namecoin block header in the bitcoin block

So the added overhead to bitcoin is adding the hash of the namecoin block header to the bitcoin block, or 30 bytes.
The added overhead to namecoin is a merkle branch from the bitcoin block header to the namecoin block header, or roughly an O(log n) additive amount of space, where n is the size of the bitcoin block.

So if anyone would complain, it would be namecoin fans, absolutely not bitcoin fans.  However IMO a small additive space overhead is worth the security guarantees of getting all bitcoin miners verifying namecoin too.

EDIT: Re your edit.  We jump with joy and take the opportunity to do things the correct way: put both bitcoin2 and namecoin as auxilliary blocks of a more general "proof-of-work-for-hash-tree" system, whose "blocks" will be nothing more than pointers to auxilliary block chain headers.  In particular, such blocks for the primary chain will always be very tiny, and so the auxilliary chains only incur O(log n) overhead where n is the number of auxilliary chains.

The wiki page isn't very good.  Actually, were I in a less charitable mood, I'd say it sucks donkey balls. Took me several reads to "get" it, and that was only because I've read the forums extensively and was able to put the pieces together.

Summary:

Basically, they hide the namecoin block hash in the coinbase transaction of the bitcoin block, and if a hash is found for the bitcoin header that meets the namecoin difficulty standard, the namecoin chain can use the entire bitcoin header to extend the namecoin chain, even if the bitcoin difficulty target was not met.  It does not extend the header size, but it does extend the coinbase script field, which isn't a very big deal because it wasn't a fixed size to begin with.

OK, I suppose I will consider myself sold on it.  This summary belongs in the Wiki, because I couldn't gather this from what was there.

Essentially what you are saying is that reference to the BTC block chain isn't ever needed, and that there is no dependency, but rather, that NMC will accept a "proof of work" formatted for Bitcoin as a Namecoin proof of work - and tack it onto the Namecoin block chain - so long as that Bitcoin proof of work contains a reference to the most recent Namecoin block.  And that NMC will look for the merkle root not in the merkle root field (since that's reserved for Bitcoin compatibility), but in the coinbase.

As a purely abstract argument, I assume this would mean one doesn't actually need to be mining real Bitcoins, the Bitcoin block chain will never be consulted by any non-mining Namecoin client, and that a block that ends up becoming stale or rejected off the Bitcoin block chain can still remain valid on Namecoins, and in fact never need to become part of the Bitcoin block chain, if they meet the Namecoin difficulty but not Bitcoin.

If I have understood this correctly, then I hereby do a 180 and endorse the idea and apologizing for not seeing the greatness (though the documentation could have been better).

In this case, why wait till block 24000?  That could be a while, especially at the low end of this manic-depressive mining cycle.  If the Namecoin exchange, the Namecoin block explorer, the Name DNS servers, and other critical infrastructure convert, the conversion can happen pretty much any time, because there will be no functional tools or any reason for anyone to stay on the old system.

This.

But the namecoin "fans" don't know what they are wishing for ... all they see is money in their eyes from "more hashing power" ...

It is a very pernicious mod. to namecoin that has been rammed thru in a somewhat unseemly fashion imho.

The ruination of namecoin would serve as a very stern warning to any other aspirations for starting competing blockchain currencies.

Nah I don't see it quite the same. There will be 7200 nmc on average per day regardless of how it's mined. Right now namecoin is suffering from a manic depressive negative feedback loop where people rush to mine it when the difficulty is low, spiking it so no one wants to mine it anymore, making it lowregain for another cycle.  This proposal would completely solve that.

I am in favor of merging.
Why?Let's have a look:http://dot-bit.org/tools/nextDifficulty.php (http://dot-bit.org/tools/nextDifficulty.php).
If or when the majority of miners leave the network NMC is screwed.
 

The person who mined them gets them, of course.

The coins are not generated "on the bitcoin network" nor do they reside there.  They reside completely in the Namecoin block chain.  The only thing is that the block is in a different format that keeps it compatible with being submitted to Bitcoin if it also happens to satisfy the Bitcoin difficulty.  Think of it another way - instead of thinking of "dual mining", think of mining for Namecoins with a special block format that happens to be compatible with Bitcoin.

This is what I originally did not understand.  I believed that Namecoin proof of work would be stored in the Bitcoin block chain and that the namecoin client would need to consult both chains just to follow all Namecoin proof of work.  I was wrong.

The point of this change is to come up with a new format of a block that is 100% backwards compatible with Bitcoin but which also benefits the Namecoin network, the same way when they invented color analog TV, they did it with a signal that was 100% compatible with black-and-white TV's which simply ignored the color portion of the signal.

tl;dr summary? namecoin is color TV, bitcoin is black 'n white??

Merged mining works like this, you have two totally separate block chains, they are not related in any way nor does either contain any data from the other. When you mine you generate hashes that may be the solution to the current block, this is very very improbable per hash, its like a lottery where everyone generates tickets until someone finds the winning one. Normally you make tickets and check them against the Bitcoin block chain to see if they are the solution. With merged mining you create a ticket and check it against both the Bitcoin block chain and the Namecoin block chain, Bitcoin and Namecoin know nothing about each other, they are two totally different lotteries with different winning numbers, you just sent a copy of your ticket to both. Since you are sending the same ticket to two lotteries you increase your chances of winning one or the other. No Bitcoin data goes into Namecoin no Namecoin data into Bitcoin they remain totally separate, you simply run both the Namecoin and Bitcoin clients on the same machine and submit hashes to both networks, if your hash is the solution to the Namecoin block you get Namecoins if you hash is the solution to the Bitcoin block you get Bitcoins, its exactly like if you where mining on just one network, except you submit the same work twice.


Not quite tl;dr but i think its gets the point across. 

Correct. And the benefit is that both chains will tend to contain more hashes if this is done, thus making them both more secure.

Making a change in what is or is not considered a valid block can split the network. So you have to plan it way in advance, wait for the vast majority of the mining power to understand the new rules, and only then introduce blocks whose validity differs in the two schemes. And the vast majority of nodes must agree on precisely when the rules change. Otherwise, those with the old software will track a different hash chain than those with the new software.

Long-term I think the bitcoin protocol should be adapted to specifically include foreign merkle roots in a known format. This will allow people to pile bitcoin proof of work on top of anything they need without having to 'disguise' it as a dummy transaction or the like. (This could consist simply of an agreement that a particular type of transaction will be used. No actual code/format changes are likely needed.) An accepted fee of, say, .005 BTC to include one 256-bit chain root, one 256-bit merkle hash, and one 256-bit "accessory" field would do.

Okay so then that would imply that both the bitcoin and namecoin clients would have to updated the code to submit the proof of work to both block chains or no?

I guess for bitcoin since 95% generally pool mine, only the pools need to update their software to submit proof of work to the namecoin network in order to capture the majority for merged mining.

So then what will likely happen when this does take place is that since the namecoin difficulty is like 1/17th of that of the bitcoin network the difficulty will likely catch up to the bitcoin network and likely come to parity at some point in the near future.

And lastly if someone creates a proof of work that satisfies both bitcoin and namecoin at that moment they get 50 BTC and 50 NMC?

Does this sound right?

The bitcoin client doesn't have to be changed because the modified blocks are still valid and consistent with the Bitcoin protocol.  They just contain one extra number that the Bitcoin client already allows and will ignore.

Bitcoin clients would not need to update unless they wanted to participate in pooled mining and they were issuing work units. Every namecoin client would need to update.

Certainly the difficulty for namecoin would shoot up.

Yes, assuming they correctly assemble the proof of work into both a bitcoin block and a namecoin block and both blocks wind up 'winning' in their respective hash chains.

Thankyou ttk2 for this. I've been reading lots of text about this concept, and wasn't quite getting some bits of it. Now it makes more sense.

Why don't you have a donation address in your signature?

Didn't think anyone would care to donate.

12YXLzbi4hfLaUxyPswRbKW92C6h5KsVnX


Thanks! I am glad i could help.

Tiny tip sent your way. I like to spread itty bitty tips around when I find something helpful or cool.

Could you please correct this (on the web site also)

It is false (see highlighted sections that are wrong)

Namecoin data (unrelated to bitcoin) is added to the bitcoin block chain, thus making the bitcoin block chain unnecessarily larger.

Though, for those who do want to do this - look at it this way :)
Namecoin blocks are almost free.
The cost is those extra bytes added to the bitcoin block chain (i.e. disk space for everyone in bitcoin)
If you mine exclusively namecoin you are paying with your hashes and electricity (as well as the namecoin block chain disk space)
If you mine merged you are only paying with your namecoin and bitcoin block chain disk space.
What value does that put on a namecoin coin?

Technically true. I agree that those things are literally incorrect, and when you're trying to make an argument on a contentious issue, it's good to be precisely correct. Merged mining does add some bytes to the bitcoin block chain. However, lots of other things add many more bytes to the bitcoin block chain and are of much less value.

In fact, if I were designing a Bitcoin replacement/update, one of my solutions to the reducing mining payout over time would be transaction fees for securing things in the block chain -- with an efficient "secure these hashes" transaction and a per-hash transaction fee. (This transaction would have no outputs and clients would know that they have no need to store it as a transaction. Block chain pruning could discard it entirely.)

In any event, if the transaction fees don't accurately reflect the costs associated with committing bitcoin transactions to the block chain, they should be raised. Unfortunately, there's a somewhat fundamental tragedy of the commons here. One person gets the transaction fee just for including the transaction in a block, but then everyone must store that transaction forever. This is a design flaw in the Bitcoin protocol that will likely get resolved in the future.