By Bitcoin Revista - fa 6 mesos - Temps de lectura: 15 minuts
Control de monedes a dues cares
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Self custody is an essential requirement when using Bitcoin to fully benefit from all the properties that make Bitcoin valuable in the first place. To be able to truly transact without permission, benefiting from the censorship resistance of the network, you have to control your own keys. You can’t outsource that to someone else, you can’t trust the neutrality or honesty of a custodian, you must solely have direct control of corresponding private keys to your UTXOs. If you fail to do this, you will always be a second class user. Bitcoin as a system gives you almost total control over your own funds; control of custody, when it is spent and how it is spent, even the ability to completely destroy your coins through deleting your private keys.
When you outsource that direct control of the actual Bitcoin UTXOs on the network to a third party, you relinquish that control in its entirety. That’s not to say that there aren’t middle grounds to that, such as Lightning, Statechains, and other proposed second layer designs, but ignoring those for a moment, when you do not control your UTXOs directly, you do not have the ability to transact whenever and however you want. You do not have the ability to destroy and render your coins inaccessible if you want. You do not have something that is permissionless in your ownership and control.
So why do people choose not to withdraw their coins and leave them with a custodian? Some combination of apathy, lack of understanding, fear or doubt about their ability to correctly manage their own keys without losing money, or even concerns over being able to physically keep their keys safe. There are numerous reasons, and over time we will have different solutions to address the root cause. But one of the big causes for such a choice has yet to even really happen to any serious degree; the raw economics of blockspace utilization. If you only have a couple of dollars of bitcoin –or even less in the case of zapping satoshis around with things like custodial Lightning solutions– you cannot practically take control of those coins or spend them on chain cost effectively. Even when fees get that high however, it's still cost effective for a user in such a situation to handle their Bitcoin until they have enough to be able to afford to withdraw to self-custody at a reasonable cost.
That is not going to be the case forever. No matter what happens, if Bitcoin actually succeeds and becomes widely adopted for real use among normal people, that cost of blockspace is going to trend up; a tide that continues rising in sync with the growth of users forever. It will even rise without user growth whenever economic activity and money velocity picks up among the existing userbase. It is an inevitable reality, it cannot be stopped by anything short of the stagnation or complete failure of Bitcoin si mateix.
So what is the solution here? That is pretty much the root of the tug of war between the old big block versus small block divide that has been going on since the beginning of Bitcoin. Taking custody of your own bitcoin by having them sent to key pairs you control is a foundational aspect to Bitcoin, but so is being able to actually validate that a Bitcoin UTXO controlled by a key you possess was really created on-chain. The relationship between the costs of these two things is, and will forever be, an eternal tug of war between the costs of one versus the other. If you make the verification cost of blockspace cheaper and increase its availability, more people will utilize it. If you make the use of it more efficient, more people will utilize it.
You can tweak those variables all day long, back and forth, you can make computational verification cheaper, you can make blockspace use more efficient, but either one will just enable more people to use it and inevitably (unless we are all wrong about Bitcoin) lead to an increase in demand for blockspace. And that is just looking at things in a basic vacuum of economics and how demand and availability regulate each other. That isn’t even considering the actual engineering trade-offs of the specific ways to accomplish either thing, and the downside risks each optimization creates.
I hi ha moltes compensacions implicades en totes les maneres específiques d'aconseguir qualsevol d'aquests objectius. Molt. Fins i tot el protocol Lightning, amb tota la brillantor d'enginyeria al darrere, que ofereix un augment exponencial del rendiment transaccional, té limitacions i compensacions massives. És el protocol més escalable i alhora és el protocol de segona capa amb més confiança proposat fins ara en termes de rendiment versus manca de confiança. Però fins i tot té desavantatges i diferències fonamentals.
Feu clic a la imatge de dalt per subscriure-us.Lightning’s security model is reactive, meaning that the only way to ensure that you don’t lose money is to pay attention to the blockchain and react quick enough if someone tries to steal funds from you by submitting an old channel state to chain. While this is a perfectly workable solution to that problem, it is a great departure from the security model of just unilaterally holding a UTXO. All you have to do in that situation is verify once that a coin sent to you on chain was actually confirmed and then you are done. You do not have to continuously pay attention to anything after that in order to keep your money secure.
This fundamental difference between using bitcoin through Lightning rather than directly on chain will have a lot of consequences for users with less money or cost tolerance for blockspace. The higher the average fee rate trends up, the more people will be pushed into locking their coins on Lightning to be able to actually spend them more cost effectively. It doesn’t even begin to end there with them being forced into a reactive security model though. Lightning routes payments through Hash Time Lock Contracts to guarantee that the money is fully sent or fully refunded across an entire payment route. This is actually never done for small value payments that are not cost effective to enforce on the blockchain if necessary. Those 1-2 satoshi payments getting zapped around for fun are sent in an entirely trusted fashion without using HTLCs and just hoping no one along the path screws up or refuses to cooperate. As fees rise on the base layer, this will have to be done for larger and larger payments. It makes zero economic sense to spend $5 in fees to enforce a payment worth only $1. Imagine $10 fees, $20 fees, etc. As the fee market matures and the base level of fees rise, even the nature of payments across the Lightning Network will fundamentally change, moving from a trustless system enforceable on-chain to one ultimately depending on honest behavior.
La mateixa dinàmica sagnarà si un usuari pot fins i tot obrir i mantenir un canal Lightning en primer lloc (o si algú més voldrà destinar liquiditat a aquest canal perquè l'usuari tingui capacitat de recepció). Si costarà 10 dòlars fer transaccions a la cadena, llavors esteu immediatament al ganxo per 20 dòlars, suposant que les tarifes no empitjoren encara, per obrir i tancar, inevitablement, aquest canal. Si heu de tancar de manera no cooperativa, fins i tot sense cap HTLC en vol, és de 30 dòlars perquè aquest tancament requereix dues transaccions. Quants diners haurà d'invertir la gent en un canal per considerar les tarifes que val la pena? Les coses començaran a ser molt excloents molt ràpidament quan les tarifes comencen a créixer definitivament quan la demanda d'espai de blocs es saturi.
So what does this mean? Lightning isn’t enough. It gives a lot more headroom in scaling self-custody, but it does not completely solve the problem and will itself wind up subjected to the exact same economic scaling issues that are present on the base layer of the blockchain. Not to mention introducing new security assumptions in the process along the way. It’s like building up a barrier of sandbags around your house in a flood; it will keep your house safe as long as the water level doesn’t rise above it. But if we are right about Bitcoin and its adoption continues unabated, the water level will keep rising well above the top of that barrier. Lightning by itself is not enough to raise the barrier much higher.
Quina alternativa concreta i desplegada pot elevar-lo més amunt? Les cadenes d'estat són un exemple concret. Poden aconseguir un augment massiu de l'eficiència de l'ús de l'espai de blocs, però sorpresa sorpresa –no hauria de ser una sorpresa–, introdueixen encara més compensacions que Lightning. Quan tractes amb un canal Lightning, l'obres a una contrapart específica i aquesta és l'única persona amb qui pots interactuar. Per canviar la persona amb qui estàs interactuant per accedir a les rutes a altres persones, en realitat has de tancar aquest canal a la cadena i obrir-ne un de nou amb una altra persona. Statechains canvien completament la dinàmica allà.
Amb una cadena estatal, podeu transferir monedes a qualsevol persona nova amb qui no hàgiu interactuat abans completament fora de la cadena. Però només podeu transferir la totalitat de l'UTXO i hi ha implicat un tercer arbitratge. Desavantatge número u; un cop tanqueu una moneda en una cadena estatal, tot es pot transferir fora de la cadena, però només tot alhora. En segon lloc, tota la manera en què funciona és confiar essencialment en un tercer neutral per cooperar exclusivament amb el propietari actual. La manera en què s'aplica a la cadena es pot fer de diverses maneres diferents, però la llarga i la curta és que el propietari original crea una cadena estatal bloquejant monedes a l'estil Lightning amb un operador de serveis i obté una transacció de retirada prèviament signada que està tancat com a Lightning per retirar-se unilateralment. El truc és que quan configureu el "multisig", utilitzeu un esquema com Schnorr on només hi ha una sola clau de la qual cada part té una part. Hi ha protocols criptogràfics que es poden utilitzar per regenerar claus compartides de manera que els usuaris successius i l'operador del servei acabin amb diferents claus compartides, igualant la mateixa clau pública. Quan transferiu una cadena d'estats, l'emissor, el receptor i l'operador participen en un protocol fora de la cadena i l'operador suprimeix la seva part antiga per al propietari anterior, de manera que ni tan sols són capaços de signar alguna cosa en cooperació amb aquest usuari.
Lightning és essencialment un acord unilateral entre dos usuaris en el qual qualsevol pot fer complir la cadena en qualsevol moment, sempre que prestin atenció a la cadena de blocs. Però no podeu canviar els participants del canal en aquest acord sense entrar en cadena i pagar les tarifes necessàries. A causa de com funciona el mecanisme de seguretat de sancions (treu tots els diners d'algú que va intentar enganyar amb un estat antic), tampoc no pots crear aquests acords entre més de dues persones. És (pràcticament, no literalment, a causa del cost computacional) impossible trobar una manera d'assignar la culpa i penalitzar només la part correcta en acords entre més de dues persones.
Les cadenes estatals són el mateix tipus d'acord, excepte el de final obert en el qual es pot implicar, sempre que qui vulgui estar disposat a confiar en l'operador del servei, que cal tenir en compte que es pot federar entre un grup, i es pot fer complir unilateralment com sempre que mireu la cadena de blocs i els operadors del servei es comporten amb honestedat.
El que va passar aquí en aquesta progressió, de Lightning a Statechain, és que heu fet possible que més de dues persones interactuïn de manera segura fora de la cadena si estan disposades a confiar en una part neutral per fer complir un resultat honest. Així que es va obtenir una gran escalabilitat pel cost d'introduir confiança a més del requisit ja existent per mantenir-se en línia i veure la cadena de blocs.
Per què? Perquè aquesta és realment l'única manera d'aconseguir aquesta major escalabilitat sense afegir noves funcionalitats a la cadena de blocs. Afegiu confiança a la imatge. Tal com estan les coses ara, probablement podem aconseguir una gran escalabilitat a la cadena de blocs sense recórrer a la custòdia total confiant en una sola entitat per no robar els vostres diners, però cada pas que fem cap a una major escalabilitat introduirà més confiança.
No hi ha manera d'evitar això; o bé s'ha d'afegir una nova funcionalitat a la cadena de blocs o nosaltres, com a col·lectiu de diferents grups d'usuaris, hem d'acceptar que així anirà. Més confiança a les vores per a casos d'ús de menor valor i usuaris de menor valor net.
There has been quite a lot of concern and discussion around this entire dynamic this year. The higher the average fee trends for space in a block, the more people will be priced out of using Bitcoin, even when you take into account things like the Lightning Network. Inscriptions and Ordinals caused a massive divide in the more active minority of people in this space, and all of it at the root was centered around the dynamic of one use case potentially raising the fees for blockspace to the point that another use case was priced out of being viable on Bitcoin.
It has been a very illuminating year so far watching people call Taproot a mistake, rally around publicly decrying the incompetence of developers in not realizing what they did, and dig in further into a dogmatic attitude. “Never upgrade or change Bitcoin again because it is perfect and infallible.” These same people in a vast overlap tend to also be the same people championing Bitcoin as a tool for self-sovereignty. They seem to always be the same people preaching self custody as a magic remedy for everything, and when scaling problems get brought up? Oh, Lightning is THE solution to that. Then they point at Ordinals and inscriptions again and start screaming about how one use case will price out another one, and so that bad one has to be stopped.
It is missing the forest for the trees. Any use of bitcoin that is profitable and cost effective to deal with demand is going to happen. There is literally no way to stop that, and Bitcoiners convincing themselves they can are fooling themselves. All of the backlash against Ordinals and Inscriptions very quickly led to people intentionally doing even more costly things like STAMPS, which instead of using witness data that doesn’t have to be stored in the UTXO set, puts their data inside the actual UTXOs. Rather than acknowledging the reality that if people think it is profitable to pay for blockspace they will, many people are falling victim to a knee jerk reaction of trying to stop what they think is bad while completely ignoring the reality that there are other worse ways to accomplish the same thing anyway if it makes economic sense. An impulsive reaction to the rise of Ordinals and Inscriptions is dragging down the entire attention span of involved people in this space into a pit of wasted efforts to stop things causing fee pressure that they don’t agree with instead of considering how to adapt and scale things they do agree with to that fee pressure.
Click the above image to download the PDF.Un bon percentatge de les persones que participen així estan literalment discutint amb el vent. Ens estan intentant dir-nos que deixem de bufar perquè està tombant coses en lloc de lligar les coses o ponderar els fonaments per resistir-los. Si bloquegeu o censureu les inscripcions amb èxit, la gent només utilitzarà STAMPS, o OP_RETURN, o tècniques encara més malbaratadores de recursos de xarxa.
Ultimately no technical filter will be good enough to stop people from doing dumb or non-monetary things with the Bitcoin network. The only filter that will successfully stop anything from being done on Bitcoin is economics. And that filter is equally created and equally affects every use of Bitcoin. It’s time to stop trying to fight externalities driven by economic demand and try to counter them through improving efficiency.
Si tu creus Bitcoin’s primary value and purpose is to transfer value, then rather than obsess over somehow stopping all other uses of Bitcoin, you should be focused on considering the trade offs of different mechanisms that can improve its efficiency in transferring value. You are either going to have to choose between progressively adding more trust to things in order to accomplish that, or adding new features to the Bitcoin protocol itself to build more efficient things without depending on trust.
Buraq, l'infame assassí de Lightning, ha proposat recentment TBDxxx, un nou protocol de segona capa. Es tracta bàsicament d'un gran sistema de cadena d'estats/efectiu multipartícip que no té la custòdia, no requereix confiar en l'operador del servei com una cadena estatal i pot agrupar molts usuaris en un únic UTXO a la cadena. Això requereix ANYPREVOUT(APO) o CHECKTEMPLATEVERIFY(CTV) per funcionar, de manera que necessita un canvi de consens. Les fàbriques de canal són una manera d'agafar un únic UTXO i apilar els canals Lightning uns sobre els altres, de manera que un UTXO pot representar desenes d'usuaris que tenen un canal Lightning normal a la part superior. Això també requereix ANYPREVOUT.
Both of these proposals can scale the use of Bitcoin to transfer value much further than Lightning can now, but ultimately both of them are subject to the same economic fee pressure that Lightning and on-chain use are. To join one of these multiparty channel pools, or exit one, or enforce something non-cooperatively on chain you still have to pay fees. For something like a channel factory this will involve one person who needs to close or enforce something actually unfurling and closing (fully or partially) the entire channel factory with everyone in it, creating costs and on-chain implications for everyone. Even despite accomplishing a huge increase in scalability without trust, it still falls victim to the effects of the blockspace market maturing.
Per mitigar (no resoldre) això, probablement necessitarem encara més codis OP. Coses com OP_EVICT o TAPLEAFUPDATEVERIFY. OP_EVICT permet que un grup expulsi col·lectivament un membre no cooperatiu d'un canal multipartícip sense tancar ni afectar ningú més amb una sola transacció amb una entrada i dues sortides. Això no resol el problema, però ho fa molt més eficient en permetre que una persona sigui desallotjada amb una petjada a la cadena molt més petita. TLUV aconsegueix el mateix, excepte que en lloc que tothom expulsi algú, permet a un sol usuari retirar tots els seus fons sense interrompre ningú ni necessitar que ningú més cooperi.
To address more of the issues, we need to make more changes to Bitcoin. There’s no way around that. Taproot “opened the door” to Inscriptions in the sense that it relaxed limits enough for people to go nuts with it, but they were already possible before Taproot. You can look at Taproot as having provided efficiency gains for both monetary use cases as well as non-monetary use cases. It made multisig the same size as a regular single sig address, which helps make using a higher security set up for keys or second layer protocols cheaper, but it also made it cheaper to inscribe arbitrary data.
Two sides of the same coin. And that is how it is. Same as it ever was. Making use of the blockchain more efficient is not always going to improve solely the use case you want, but it is absolutely necessary to scale Bitcoin in a way that is self-sovereign and self-custodial. It’s time to either accept that and start considering the reality of finding the optimal efficiency gains for value transfer with the least efficiency gains for detrimental or non-value transfer uses, or it’s time to accept that the only way to scale value transfer is to introduce trust.
A good number of people in this space have already made their choice one way or another, but there is a large contingent of people in the middle who refuse to accept either. This loud group in the middle needs to wake up and smell the coffee, and accept the reality of the situation. This is how blockchains work. Pick one; either brace yourself to accept the injection of trust into things, or accept the reality that changes need to happen. You can tell yourself all day long that you don’t have to choose, but your actions in attacking the notion of any change to Bitcoin at all while simultaneously championing self-custodial Bitcoin as a solution for the world are implicitly making the choice to accept more trust being introduced into the system, whether you want to acknowledge that or not.
This article is featured in Bitcoin Revista "El problema de la retirada". Feu clic aquí per subscriure-us ara.
Un fullet en PDF d'aquest article està disponible per a descarregar.
Font original: Bitcoin Magazine