Bitcoin Forum

Can somebody explain to me why the Bitcoin scripting system is purposefully not Turing-complete? To make malicious programs difficult to develop (I guess)? Or because it was difficult to make it Turing-complete?

Bitcoin uses a scripting system for transactions. Forth-like, Script is simple, stack-based, and processed from left to right. It is purposefully not Turing-complete, with no loops. (https://en.bitcoin.it/wiki/Script)

Attack prevention.  With loops and recursion it becomes more difficult to limit the resources required by a script.  It would be possible to create scripts which crash nodes, scripts which take hours to validate, scripts which consume the host memory.   Any looped code can be unrolled.  The execution time of unrolled code is easy to control by limiting the length of the script.

Thanks. But I guess there must be tools that convert high level Turing-complete languages to low-level BTCscript code. Right?

One of the main selling point of Ethereum, as I understand, is that their Turing-complete programmable system permits writing complex contracts.

I believe Ethereum is backing off from that claim and it will not be Turing complete.   Generally the higher the complexity of the environment the higher the chance of undetected flaws, bugs, and exploits.   The idea that one would want a complex Turing complete (or quasi turing complete) scripting language, combined with the overhead of a decentralized network, to process the transfer of money seems a very dubious proposition.   I want my financial processing engine to be as lightweight and simple as possible.  Higher level functionality can be built on top of the network.

this was discussed here: https://bitcointalk.org/index.php?topic=431513.msg6509979#msg6509979

as is already suggested, they were purposefully made to be non-turing complete.  Actually what it takes to compute a TX is entirely bounded.  See: The Halting Problem, ie. we know the little programs put inside bitcoin scripts must eventually end.


well what exactly do they have left as a value proposition?

https://i.imgur.com/weLUijK.png

-bm

Are you suggesting they ever had one to begin with?

Remember that Ethereum's promise from the beginning was allowing you to do computations on a global distributed computer with no privacy and cycle times in the milliHertz range.

Nobody ever bothered to ask if there really was a market for this service in the first place.

what's hilarious is they're releasing videos on people using Ethereum?

https://www.youtube.com/watch?v=9WNyupn8pvw

they clearly haven't even worked out the basics yet, but they're advertising all these end-user GUIs and such?

such wow.

-bm

Also: Aston Kutcher likes it!  can you say, paid-for-PR?

-bm

Where/what are the use-cases for these complex contracts?

just-dice could be completly onchain (including user deposits for bankroll and interest).
but most know what happend when satoshi-dice was onchain ;)

Actually I don't. What happened?

(And if whatever it was doing was done on bitcoin, you didn't answer my original question about ethereum)

too much transaction which bloated the chain.
as many try martingale wth dice sites i think this would happen with this contract.

and what's going to happen to all these new Block Chain Piggypack schemes(counterparty, color coins, etc.)?

it poses a huge systemic risk to Bitcoin and many other serious dangers I wont get into here.

-bm

that was part of my case in the thread I linked above.

They are(were?) trying to create an environment for scripting a block chain but are ignoring the massive computational complexities that these problems imply.  The only way to achieve these functions is on a case-by-case basis.  Each one has distinct processor/storage/usability requirements.

-bm

I posted this in another thread, but I think it answers your question:

https://i.imgur.com/OypDNTl.png

The above chart is distorted by the "on-chain" gambling bubble of mid 2012 to mid 2013.  Most gambling now takes place off-chain (in fact, just-dice.com processes over 100 bets per second).  If we attempt to remove the "on-chain gambling" bubble to get a better sense of organic growth in the number of transactions per day in the bitcoin economy, we finds its been growing exponentially at approximately 320% per year.  

https://i.imgur.com/1MHBBDw.png

I think we'll never know what really happened there. SD's traffic fell off almost instantly with the change back to private ownership. I believe, and I think that the data supports, that there was activity going on to pump the level of traffic there— though for what exact motivations are anyone's guess. :) Hideously inefficient in any case, and not even necessary for security.

also related to the COIN_DUST episode.  It raises the basic question of - what is *clever use* of Bitcoin and what is *abuse* of Bitcoin.

we're about to explore that territory and I dont think some parties are going to like the answer.

-bm

Well there is no such thing as too many transactions.  The problem was that the site used a "payment" of a single satoshi as notification that a player lost.  This bloats the UXTO which is a more critical resources.  Spent tx can be pruned but to validate future txs and blocks nodes need to maintain a copy of the UXTO.  Normally most outputs in the UXTO are eventually spent (and create new outputs) so the UXTO grows much slower than the overall blockchain.  The problem with single satoshi outputs is they are never economical to spend so they probably will never spend.  This means the UXTO starts growing on the same order as the overall blockchain.

Site like this are one reason the dust rules were created.  They discourage creating outputs that will probably never be spent to prevent them from remaining in the UXTO forever.

thanks DnT for clarifying.

but i think my point about some (eg dice-like) contracts would create many more transactions still stands. afaik there is no coin which could handle a large  tx volume (though 100 bets/sec might be possible in the future).

surely there must be SOME limit there.  We can't be sending terabytes of transactions data to all nodes at all times.  The problem may seem remote until you start to see transactions multiply by number of coin colors + whatever other sorts of trading applications and the like emerge.  You can't just stick anything you want on the blockchain.  This poses a systemic risk to Bitcoin.

transactions don't require a limit for so long as they reflect the value of the currency.  These other 'rider' networks like Color Coins don't necessarily have any relationship to the price of BTC at all and that's going to be the basic problem from which many technological issues will emerge.

-bm

Not true that implies Bitcoin will eventually become so popular it fails.  Eventually 1000 merchants or 10,000 merchants or 100,000 merchants would generate the same tx volume.   Fees will keep tx usage in line.   A 1 bit fee is cheap if you are transferring 1,000,000 bits but you might think twice if you are trying to transfer 2 bits.   Still fees can't resolve the problem of UXTO bloat and that was a problem.

actually you are right.
i think that bitcoin will mainly be used as a clearence network between bitpay like institutions and exchanges.

Yes but it is self resolving.  Someday a large number of merchants combined may produce 10x as many txs the dice site.  Does that mean Bitcoin is doomed.   It is inevitable it will get so popular it will produce "too many transactions" and then die?   Of course not.  As tx volume rises, tx will compete for space in the next block and fees will discourage low value transactions (like martingaling 100 sat starts to look stupid when it will cost you 10x in fees).


They still have to pay fees like any other tx.  If tx volumes rise sufficiently those colored coins concepts may find themselves stuck on a network where moving their assets is prohibitively expensive.   

Well, they could if bitcoin were designed a bit differently, but I don't know that its worth it.

Imagine that each txout created by a transaction reduced the permitted block size by— say— 100 bytes and every txout consumed by a transaction decreases its the transaction's effective size by up to 100 bytes per scriptsig (clamped to not result in a negative size for each scriptsig)... and then there was some sanity limit on the real size to prevent silly attacks.

Then in that case the transactions that are creating txouts are effectively prepaying for the space the signatures will take to consume them. This would help a lot with the UTXO bloat.  I don't think anything short of utxo expiration of some form can be a complete solution, but if the system worked a bit differently fees would be a much better tool.

to further back up my point, here are some trading stats from the NYSE.

http://www.allcountries.org/uscensus/835_volume_of_trading_on_new_york.html

so in 1999, we had daily highs of several billion trades a day.  Since 2000 this has increased considerably.

now keep in mind that under the current schedule for ie. Color Coins, *creating* a new ticker costs a few cents.  Thus it's reasonable to expect even more than 1 billion transactions a day.  I think you're ignoring the problem because you would rather attention not be going to alternatives like NXT that do have the possibility of supporting this sort of volume.  Volume, network character, and processing seem to be completely ignored by Ethereum altogether.

-bm

I am not ignoring the "problem".  Volume on NYSE is in the billions of shares because fees are insanely low, less than $0.00004 USD net (88 satoshis) per share traded.   Any assets traded on the blockchain would need to compete with bitcoin transactions and fees will probably be at least a magnitude higher.   If NXT is more economical for colored coins then the assets will move there so I don't see a problem either way. 

There is no such thing as "too many transactions" what types of transactions are viable will change over time depends on the cost and limits imposed by the network.  For example the US fedwire (bank wire) network processed 134,244,177 transactions last year.  That works out to about 4 tps.

there's also another important issue.

the payoff of an attack becomes exponentially higher.  The chain could be carrying trillions of dollars in securities and such.  Therefore the payoff of reversing transactions are similarly increased.  This creates greater incentives, and in this age where hashing power is brokered and transfered to different hands instantly- an attack starts to appear more immanent.

if the chain were suddenly thought to be inviable, what would happen to the holders of these assets?  it would be an utter disaster.

this problem doesn't exist in NXT because the cost of an attack scales perfectly in ratio to the cost of NXT, whereas in Bitcoin it scales to the cost of hashing power.

-bm

If NXT provides better security for assets then assets will be transacted on that network.   So what is the problem again?

problem for who?

this would be a problem for Color Coins and Counterparty and certainly anyone who chose to invest in assets on those networks.

I predict there will be a tension between those who maintain the core features of Bitcoin(and it's status as the reserve cryptocurrency) and those who are attempting to overlay new features.  These new features may seriously threaten the basic functions of Bitcoin.

-bm

Agreed.

Agreed. 

Disagree.

what is stopping these sorts of initiatives from abusing the network?

-bm

DOGETHEREUM.

  :)

Remember, if you reverse a colored-coin coinjoin trade for bitcoins, then all it does is gives you back your colored coins and gives the other person back their bitcoins.  With coinjoin, the "trade" is a single transaction, so why would you reverse it after 30 minutes? 

That being said, the bitcoin market cap would most likely be measured in trillions of dollars if "trillions of dollars in securities and such" were tokenized via colored coins.  The higher the price of bitcoin, the more costly it is to attempt to reverse a transaction (at a given coinbase reward). 

how does that work?  the cost to reverse a transaction is related to the cost of HASHING POWER, not the price of bitcoin.

-bm

Q: Imagine that gold is trading at $1000 oz and anyone can dig it out of the ground and refine it for $500 / oz after all expenses and labor have been paid.  What would happen?

A: A bunch of people would start mining like crazy and selling for a risk-free $500 profit.  This would initially increase supply (thereby dropping the price) and eventually increase the difficult of mining it (e.g., all the easy $500 gold will get mined quickly).  Eventually, the price of gold would decrease to, say ~$800, and the cost to mine it would increase to, say ~$800.  This is what happens in a competitive free market.  The cost of production (cost of hashing power) approaches the market value of the commodity (BTC inflation rate).  

youre ignoring a very important point.  Is a troy ounce of silver more valuable than a 5000 dollar bill?  simply because it's shiny and heavy?

if we can establish this balance of power without the hashing gear, then is performs the same function and thus has the same value.  Ergo, NXT is valuable.  QED.

-bm

The fifth most valuable by crypto by marketcap right now.  Which is something.

most of the cryptocoins are pump and dump schemes.  The market cap is measured by some weak function of sales, but the owners could be holding onto 95%+ of the coin.

NXT is not in the above category.

-bm

It is generally accepted that the market value of a commodity and the cost to produce that commodity tend to the same price in a free and competitive market.  This rule doesn't apply to US dollars because US dollars are not commodities and producing them isn't a competitive free market. 

Nxt tokens, on the other hand, are more like shares in a p2p company than commodities.  The market value of the Nxt network should reflect the present value of all future (discounted) cash flows. 

What do you think the P/E ratio for the Nxt network would be today?

actually that was recently discussed.  Someone calculated the value at something comparable to an American savings account(cant confirm that though).


these are not concrete economics ideas, sorry.  This is the gold bug mindset and as the story has been told countless times this ignores the effects of credit, innovation and imho the entire premise of civilization itself.  Is man just a resource extractor?


more or less true.  It's not just cash flows because the software also supports(and charges for) asset issuance, trades, and other upcoming features like credit and virtual corporations.

-bm

What does this have to do with gold other than gold being an example of a commodity?  The cost to produce corn tends to the market price of corn, the cost to produce aluminum tends to the market price for aluminum, the cost to produce canola oil tends to the market price for canola oil.  The reason is very simple: if the market price for corn is significantly greater than the cost of production, farmers will plant more corn and less potatoes to earn a greater profit. This action will increase the supply of corn, which will tend to reduce its market price, and eventually bring the profit margin for growing corn in line with other produce that could be produced on the same farm.   

When I say cash flows I mean money, not shares of Nxt.  If the software "supports (and charges for) asset issuance, trades, and other upcoming features like credit and virtual corporations," then the Nxt network should earn money for that service and distribute it to its share holders.  

I suppose the way Nxt earns money is by people buying Nxt (with bitcoin for example) for the purpose of consuming their Nxt tokens to buy some service (rather than forging).  This is what gives you the "E" in the P/E ratio.  So if it costs $1 to issue a "virtual corporation" and that $1 gets used up (distributed across the network to forgers), then the network earned $1.  

I did some quick calculations and at a 10% cost of capital (cryptos are risky), the Nxt network would need to consume about $10,400 / day in fees (for transactions, issuing virtual companies and assets, etc.) to support it's current $38,000,000 market cap.

I'm trying to find out how much the Nxt network forgers earn per day on average, but I can't find the information.  Do you have data on the number of transactions per day and total amount of fees paid to forgers?  

Peter,  is the market for microchips related to the cost of sand?

after all microchips are made out of silicon right?

do you have any more pulp fiction economics to share with us?

-bm

ps.  ;D

that's precisely what happens.  The TX fees go to the owners of NXT in proportion to their holdings(roughly).  It's a stochastic process.


you are quite confused sir.  When we speak of P/E in NXT we're talking about how much TX fees you earn per NXT.  What you just mentioned here is APPRECIATION or Capital Gains, that's not P/E. 

-bm

No.

That's more or less the definition of 'Turing-complete' - if you have a Turing-complete language, then anything that can be expressed in it can be translated into any other Turing-complete language. 

The reason they're called that is because Alan Turing proved a result in computability theory that showed all such languages are absolutely equivalent in terms of what they can express.

If you have something that isn't a Turing-complete language, then it is fundamentally not able to express some set of algorithms in the set that Turing-complete languages can express.

IOW, if you're writing in a Turing-complete language, then much of what you write can never be expressed in BTC's script language.  Ever.  At all. 

I'm not sure if you are being intentionally obtuse, or if you actually don't understand:

The market value of a commodity microchips and the cost to produce that commodity those microchips tend to the same price in a free and competitive market.

If the market price for "Commodity Microchip A" was vastly greater than its cost of production, then manufacturers would make more Microchip As and less Microchip Bs to earn a greater profit.  This free-market dynamic acts to bring the cost of production inline with the market price of that commodity. 

This is only true for commodities, however.  Take something like 20nm SHA256 ASICs for bitcoin mining.  The market price for these ASICs is much higher than the cost of production because this technology is not yet commoditized.  Only certain companies have the IP/trade-secrets for this technology, which means they can earn very high profits (far above the cost of production) since they have few competitors.  But what we will see over the next few years is more players developing their own SHA256 ASICs to compete for the large profit margins currently enjoyed by KNCMiner, etc.  This will drive the price of these ASICs down until they eventually become a commodity like a standard 12-bit analog-to-digital converter.

You're on point as usual Peter.

James D'angelo recently said a SHA-256 chip is a relatively simple chip,
which really surprised me, so it could happen fairly quickly.

Yes and no, a SHA256 chip is quite simple but each mining chip is actually more complex as it includes many parallel SHA256 engines so a similar number of transistors to a standard CPU. Not only that, but 20nm is smaller than you manufacture most chips except for CPUs. Most micro-controllers and other ASICs are built using a far cheaper 90nm process.

On top of that, heat dissipation is incredibly important with bitcoin miners as they run continuously. This involves some very careful circuit design to distribute the production of heat over the whole surface of the chip and ensure that thermal runaway doesn't occur.

"to the cost of NXT" ....eeerrr.... which is precisely zero?

What stops you as an early adopter of NXT once you sell out  to join an alternate chain of NXT and reverse all transactions at no cost? So you propose  a solution in which late adopters always depend on earliest adopters good faith to keep the longest chain ownest?

how exactly do you figure the cost of NXT is ZERO?

the cost of NXT is not zero and as more value becomes vested in the chain, the trading value of NXT increases(the detente scenario).  This is compounded to the fact that NXT also generates TX fees.

It's been discussed already, if someone were to try and bite off a significant chunk of NXT the price would multiply.  To get a stake capable of an attack?  Not even sure if that would even be possible at this point.

-bm

Except for the fact that I have demonstrated here (https://bitcointalk.org/index.php?topic=609457.msg6834702#msg6834702) that NXT is trivial to attack with only a small stake and a small amount of computational power.

you haven't demonstrated that.

-bm

What do you mean? What are these arguments brought here?

Once people sell out they can join a StakeUndo service like http://www.bitundo.com/ and produce their own parallel chain. Say currently 1% of coins is used to secure the network people owning at some point in the past 2% will do it.  Once such pool is set up I ll be happy to join... I will want my stake back.. It costs me nothing anyway.

Thinking this a bit further .... One with a small stake can buy and sell from  different exchanges (transfer from exchanges to exchanges to different accounts by mixing) and acquire stake history of much larger proportions than his current stake ..... Can acquire additional stake history by running other services like mixing, lending stake power and running sevices like casino or stake vaults..... This can give a person or a group of people enormous stake history to attack without even owning much at the first place....  Is this a joke?

Really?  

Seriously, you are going to insist on baiting someone into demonstrating this attack before you believe in it?  

You just like to watch the world burn, huh?

so far what Im seeing here are a series of broken arguments, invalid premises, personal profit motives, and standard web forum showboating.

-bm

Ok so I haven't produced a real world demonstration, but I have essentially given you the pseudocode. All I need to do now is get an NXT stake and figure out how to compile a custom NXT client. No one has given me any reason why this wouldn't work.

maybe no one cares what your theories are?   ;D

it's a conclusion that is perfectly plausible but perhaps not so rewarding personally.

-bm

Maybe not! I'm interested in these attack models, whether it is NXT, mastercoin, bitcoin, maidsafe, bytecoin, peercoin... They all have very interesting attack surfaces (and many bugs). Other people can engage in the debate or not, it is up to them.

I would love it if more people actually looked into the implementations of these protocols, actually went bug hunting and tried to understand how it all works at the byte level. All of these coins are experimental. The idea is to break them and then fix them not to try to defend the existing code at all cost.

I did link the core NXT devs your postings and they thought they were LOL.

have a nice day!

http://www.intergalactic-academy.net/wp-content/uploads/2011/10/e.gif

-bm

what is a 'commodity' Peter?

'co' = together

'mod' = measure

something that is communally measured.  For instance we made milk a *commodity* when we developed ways to measure the quality and quantity of milk.

I dont know it seems you're obsessed somehow with the price of hashing gear.  I don't really care because I think it's irrelevant and most people who seem to be present in these arguments are those who are invested in it somehow.  I figure that sometime in the past few years someone capitalized on both Bitcoin, the engineering muscle that defines/develops/justifies it, and the gigahash hardware.  Such an investment would be very valuable because they could offer under-the-table insurance for the chain(and it *just so happens* that such offerings popped up around this time).  Actually not so long ago there was an IBM exec hovering around the Color Coin project, presumably he saw an opportunity for hardware sales.

things like NXT threaten such a profit nexus because it invalidates their entire premise of worth.

it's very sad. :( :( :(

-bm

Honestly , what is the point of having a debate about the issues if you're going to resort to ad hominems or appeals to authority? He just asked if we can look at the actual code.

Sorry but no one gives a fat fiddler's fuck just because you posted a huge emoticon and reported some secondhand LOLing.  Can we please at least discuss the issues on their own merits?

Jonald, give me a break will you?

I've been laying down one rock solid argument after another on here.  D&T basically had a hissy fit because I pointed out that his stance suggested he thought bitcoin was flawed.  This guy 'telepathetic' has some people laughing really.  If he thinks he's so tough then go ahead and put your money where you mouth is?

fact is he's probably some long termer here posting under a new id because he knows his arguments are complete !@#$.

FUD FUD FUD.

-bm

Id like to note also that someone opened up a short sale window on the NXT exchange today.

NXT BEARS REJOICE!

https://nxtforum.org/assets-board/official-nxtshort-thread-faq/

-bm

If we all buy some nxt, will you just shut up?

(Kidding)

;-)