In 5 minutes ?
 

Probably the most obviously correct analysis !

That is true.  However, one may very well define mathematical problems of which the computation cannot be performed in the observable universe, at least, with a given algorithm.

I would think that we start to reach some reasonable upper limit of "number of steps in a computation that the observable universe can perform" if we consider the number of Planck "volumes" in the estimated state space of the observable universe.

That's a smart point ! If we can count on the fact that there will never be a hard fork changing this total, of course.

I always wondered why Satoshi applied Ripemd-160 after SHA-256 for the address, that seemed inconsistent to me.  One can say that this was meant to save some room, but there are many other occasions where a lot of room has been wasted.  For instance, the fact of posting, in a transaction input, as well the signature as the public key is redundant: one can recover the public key from the signature and the message, which would save the room for the key (256 bits in compressed format).  Also, it is strange to have a 256 bit transaction hash: it is hard to think that one would need 256 bits for the transaction, and only 160 bits for the address.

To me, there were 2 possible logical values for the address size: 128 bits, or 256 bits.  128 bits, because this is the intrinsic security level of the ECDS with 256 bit keys ; and 256 bits because this is the total entropy in the key.  160 bits is a strange compromise.  The idea that there could have been a back door in SHA-256, and that RIPEMD-160, of different origin, might have another back door, but both of them together, are "safe" sounds weird, and not a good reason to change the number of bits.  One could have used 2 times RIPEMD-160 on 128 bit parts of the 256 bit hash if that were the problem, to keep 256 bits.

As the number of satoshis is 2^51, in fact, there can, as you rightly point out, never be more than 2^51 valid UTXO at a given moment, so 128 bits would in fact be enough ; but given the wasting of room with the 256 bit transaction hash, and the publishing of both signature and key, keeping the full entropy of the key with a 256 bit address would have been the maximally safe option. 

This used to exist, in a rudimentary way: usenet, and NNTP. 
For the younger ones:

https://en.wikipedia.org/wiki/Usenet

The link between the miner oligarchy and the LN channels is attractive ; but LN nodes need, in the first place, a HUGE STASH, because they need to commit coins to every of their customers links.  I'm not sure that miners are sitting on a huge amount of stash.  I think the link will be commercial: LN hubs (owners of huge stash of coins) will agree to buy exclusive room on the chain (they need this to be able to settle for sure).


I don't see how this can be the case, honestly.  After all, you can open your hub on just any server somewhere in the world, and nobody is to know who you are for real.  

But in fact, all of this is totally deluded in a way, because bitcoin is not a currency.  Crypto is not a currency.  It is a speculative asset, and this shows more and more with the current rise of alt coins.  Crypto, with its built-in deflationary spiral, is optimal as a kind of complicated derivative, and is not at all a means of payment.    So all this 'banking' delusion is never going to happen for real.  We're assisting to the definitive transformation of crypto into a huge derivative-like speculative market, with as a main purpose the greater-fool game and the trader's game of getting money out of the hands of a competing gambler ; and with a profitable industry around it leaching off fees from this gambler's game.  

Of course, as a small application, these speculative assets can also relatively easily be transmitted to others in exchange of goods and services.  But this is a very minor, almost parasitic, application of crypto.  Crypto is derivatives finance in the wild.  It has not much to do with "money to pay for stuff" like banking and VISA.

I agree fully.  The problem with LN is not so much the "fractional reserve banking", but the fact that a user is tied to a banker, who can charge fees for his services, can report any spending and earnings, can require KYC/AML, and can give you a permission or not to transact.  Of course, you can always settle and free yourself from your banker... at least, if you can obtain room on the chain, which is maybe not free, but may also be sold out exclusively, if LN hubs agree on exclusive block rights with miners.

My idea is even that the above evolution is "natural".  There are no evil minds behind this, it is the natural evolution of the power structure of payment systems.  This is how we got here in the first place, not because a few men with cigars met in a room making evil plans, a few centuries ago.  Banking is just a natural emergent phenomenon in payment systems.

The fundamental problem, however, is that at that point, crypto has nothing to offer any more.  Traditional banking is then superior, because these are institutions with much more experience, trust, and legal backing.  In fact, the fiat system is then a better system than the 3-layer system with "guys on the internet", because there are rules, legal audits, legal recourse and so on, that "guys on the internet" will not have.  You can say what you want, but I trust my bank 1000 times more than my exchange.  I even trust my bank 1000 times more than the security of my wallet, or the Chinese miners, or the Core devs.

He did.  From memory, he wrote something like "only people mining new coins need to run full nodes".  (one of his first e-mails on the site of nakamoto institute).  


Yes.  To have a "decentralized" system, you need 3 non-colluding parties, none of them having more than 50% of the hash rate/consensus voting power.  So that is the bare minimum.  But you need to be sure that:

1) they don't collude (not even on non-agreed things but by independent judgement, like "we don't accept transactions from dark markets" or something of the kind)
2) one cannot make them "an offer they cannot refuse"

That's the hard part.


Thank you.  Someone else understands.

Well, I put the safety much more severe at 2^50 or 2^60, because at 2^70, there's still a chance in a million that a collision will occur.

https://bitcointalk.org/index.php?topic=1891830.msg18795938#msg18795938

That said, the conclusion is that for the moment, there's nothing to worry about, and by the time it becomes a problem, one could always increment it.

BTW, by the time it becomes worrisome, the cryptographic security of the thing becomes problematic too, because if there are 2^70 transactions on the chain (otherwise, 2^70 addresses cannot exist), and a normal spending needs nodes to look quickly through 2^70 transactions, it means that processing power is going to reduce the safety margin of a lot of things.

Most probably, bitcoin will have shut down before reaching that level.  Maybe humanity will have shut down too by then. 

I don't see how you can say that.  Ethereum is about half of the alt coin market.  Dash is not the other half, by far.  Ripple is 3 times bigger, and LTC and ETC are comparable to DASH.   Monero and NEM are each of the level of half-a-dash.

No, the alt coin market is much less monopolized than was the crypto market when bitcoin was still the monopolist.

The "leader of alt coins" has only 50% of the alt market share, while bitcoin has been, until recently a few months ago, essentially been above 80% of the market cap of crypto.

The market is becoming much, much more diversified.

The maximum block size parameter is not the parameter that leads centralization, but for some or other reason, this myth must remain intact.  The technical burden (networking, block chain storage, CPU time....) that leads to centralization is simply *the size of the network*.  You can shift this burden from storage (block size) to networking/CPU to some degree, but the technical burden per "decentralized user" is simply proportional to the size of the network (the number of users/the number of transactions). 

The only way to make that burden lighter, is to centralize.  This is already the case, for all people using light wallets are not decentralized users, but depend partially on the full nodes they trust.  If there are millions of bitcoin users, and only 5000 full nodes, we already see how people have "delegated trust".

But the technical burden is absolutely not what has driven centralization in bitcoin.  Bitcoin's *economic* parameters, and especially its PoW, have introduced much, much more centralization than the technical burden of having a big disk and networking.  No matter of how much you guys are putting your head in the sand, non-mining nodes are not a contribution to the decentralisation of the network, because they only act as P2P proxy servers of the miner-produced chain, which comes from essentially 20 nodes.

Bitcoin at this point, is a 20-node affair (with 5 of them being majority).

I didn't know that.  That's outright ridiculous, because that means that most payments won't be able to use the LN.  LN would be the "coffee network" then.  If channels are only $60,-, and they need to carry the ratio between "VISA-like" and "block chain" amount of transactions, say, 100-fold, which means that every channel needs to transact at least 100 * (average number of hops in the LN) * 2 transactions before settling, the LN is supposed to have transactions of the order of maximum $0.3.
(if there are bigger amounts, this will settle channels quicker than the ratio between the number of LN transactions, and the available space on the chain).

Mmm.

http://coinmarketcap.com/charts/#btc-percentage

At this moment, BTC is 59.2% of the crypto market (it is for the moment still 150% of the alt coin market but that's a strange way to look at it)

It is pretty ironic to see people who think they understand the long-term game theory of past evil planners, not understand the obvious "game theory" of discussion forums, thinking that discussion forums are just that: generously put up places of free speech discussion.  If access to a discussion forum is free, then you are the product, of course.  So you have to understand that, or the forum won't buy your product any more.  If you play it well, you can use the free publicity of the forum to get more audience than you would on your own, but the price to pay is that you deliver for the purpose of the forum (which is not "free speech" but looks enough like it to be credible).  In other words, a forum is a team, owned by some, and if you want to profit from the team, you have to pay your price.  Thinking that you can get your profit without paying the price, is the kind of error that leads to being banned.  So you have to understand the price you need to pay, to get out of it what you want or need.

Eh, correction: alt coins have now 66% of bitcoin's.  They have 40% of the whole crypto scene.
It is BTW interesting that about the same ratio is valid for the second one, and the rest.

Bitcoin is at $22 billion and alt coins are at $15 billion
Of these $15 billion, ETH takes about 50% and the rest, the other $7.5 billion, are in the rest of the alt coins and are diversified over several of them.

The remarkable thing is that this is new money.  This is not money that flew out of bitcoin, but it is new money flowing in (of course, market cap is a bad measure, but given that the volumes of these coins are relatively important, it is most probably not a multi-coin version of willy bot).

Most probably this is because there's less "up space" in bitcoin than there is in alt coins, and being speculative tokens, the market with one token rising was too simple, and too predictive which is in principle impossible: no market can be simple with easily predictable gains, because then the gains are already taken.  With a lot of different speculative tokens rising and falling, the fundamental uncertainty of markets can be re-established.   The next x10 gain, and the next /10 loss will be "somewhere" but nobody can pinpoint with certainty.

As long as bitcoin had the cryptocurrency de facto monopoly, "playing with alts" was somewhat "ridiculous" for "serious" gamblers, and the predictable long time rise was with bitcoin, and bitcoin only.  This is impossible in the long run in a market.  Now that bitcoin has lost its monopoly position (at least for the time being), while still a market leader, and the "competition for the crown" becomes credible, this puts alts in a different position: no more "low level inferior stuff as compared to the market monopolist", but rather as a player in the market like any other, where there is still a market leader, but with a place that is not impossible to overtake.

Once all crypto is on the same level, and being "market leader" is not naturally assigned to the first mover any more, the market will become much much more opaque, as it should be.  You won't know any more with some certainty what will be the crypto that is the market leader 20 years from now.  It will be, like with a mature stock market, a totally efficient market, that doesn't let you make any sure long term predictions.

Whether *this* particularly steep rise is already the indication of the maturing of the crypto speculative token market, or whether this is an artificial pump and dump that will soon crash down is hard to say.  But it indicates at least the future direction, which is to be expected.

It is impossible, in the long run, to have an established, and quite well-known "rising asset".  That simply doesn't make sense when enough smart money is in the market.  But to have an opaque market where an unknown today, will rise to market leadership in a decade, knowing that it can very well crash down, and leave its place to yet another one for the decade afterwards, is much more realistic and in agreement with an efficient market.

I agree totally with that.  This is a deja-vu with the dot-com bubble, I had some people in my environment totally bezerk, talking all day about the "new economy" and how all old kinds of jobs were for the silly and future poor, while dot-com tech was for the new elite.
Now, after the bubble crashed, there were a few good things coming out of that.  But not pets.com.   

I admit having been enthusiastic about it too, because of my anarchist dreams - but these are in any case destroyed with the speculative dominance of crypto.  I do think that there are interesting underground applications of crypto, and that there may be interesting stuff coming out of all of this.  But not as it is sold now to the gullible. 

But it is much worse than that.  If you open a channel with your dad, and a channel with your wife, you need to lock in half of your funds with your dad, and half of your funds with your wife, and what can be transacted in one direction is limited to that amount.  Moreover, you have to be careful not to transact all the time "from you to dad", or you will exhaust quickly your channel.  So you have to make sure that one time, you transact *towards dad* and another time *from dad*.    If dad is on a "highway" and your wife is too, then your modest amount of locked-in coins will not suffice to do the link between the highway on which your dad is, and the one on which your wife is: you will quickly run out of funds and have to settle the channel, with expensive on-chain transactions.

However, if you are a rich guy, you will be able to put up a lot of funds to "dad" and to "your wife" and your channel will live a lot longer before being exhausted.   The settlements will be much farther in between.  As such, you will be able to have more competitive LN fees than the modest guy.

This is why the "economies of scale" in LN are essentially proportional to your stake.  Mind you, you do not get BENEFIT proportional to stake, no, your ability to compete goes with your stake.  That's the equivalent of saying that the *efficiency of a miner* would go with the hash rate he has.   Now, miners have about similar efficiencies, almost independent of their hash rate, but of course the more hash rate they have, the more gain they have.  With LN, the more stake you have, the higher the *efficiency* of your channels.

With such almost linear economies of scale, only the biggest hubs can be competitive in the LN fee market.  This is why if ever the LN is up and running and people are squeezed out of the on-chain transactions by the scarcity of the transactions and the height of an on chain fee (if it is not a matter of exclusive room), it will centralize much faster than the mining population centralized, because the economies of scale are much more important in the LN, than in the mining business.

My opinion is that there's no way around it.  Whether these data centers are miners, LN banking hubs, or other forms of delegated power concentrations, the very idea that a trustless cash system must allow in principle, each participant to verify independently the:
1) validity of a right to spend
2) the non-existence of a spending transaction <--- the hard part
3) the non-existence of "counterfeiting" <---- the other hard part

means that a fungible cash system has a burden per user that grows with the size of the system.  This scaling burden per user will give rise to economies of scale by concentrating the "validation" process in "delegated trust authorities", and users preferring to trust some authority instead of suffering the burden himself.  This delegated trust will give power to the owners of those trust authorities, and that's the end of the decentralized, trustless system.

However, this can go almost unnoticed, because these authorities derive their power also from the credibility of the overall system, so in fact, these centralized stake holders have all interest in giving the impression to the user that everything is running as expected.  These centralized entities will be, in fact, the greatest stake holders in the system and will do everything to keep the system running for the users, defend the system and propagate the illusion of a decentralized system.

Of course you have.  You have to know whether a given "right of spending" (in bitcoin's language, an UTXO) has not been executed somewhere.  From the moment that you delegate that knowledge to "someone", that "someone" can collude with the right of spending owner (or is the same one), and tell you that the right to spend still exists while it is not the case.

Also, you have to know how many "rights to spend" are in circulation, to verify that nobody is counterfeiting and debasing the whole system.  If Joe and Jack have been double spending for half a year, even if you never have anything to do with Joe and Jack or their coin history, they are debasing the system you're using, which is a good thing to know.  The only way to know that Joe and Jack are not double spending, is to have a cryptographic proof of that.

If you give up on those two issues, you have given up on decentralization and trustlessness.  


But this is really not the problem.  DNS is totally different, because it gives you information of things that exist, not on things that don't exist.  The DNS system is a hierarchical system that tells you what IP address corresponds to what name, and yes, things like Kademlia can do it in a decentralized way.  But with a coin, you don't (only) need to know "what IP address corresponds to what name", but also that "no other name corresponds to that IP address", in such a way, that the delegated server has an incentive to tell you that such is not the case, that this could actually right now be assigned even though you don't know, and that the server having that information may very well not be online.

This can only be the case if there is a common knowledge of which you can verify yourself, continuously, whether spending of the same right to spend is being transacted somewhere else right now, or whether an address is "locked in" (style LN / sidechains / ....).

I don't think there is any way out, unless you give up on trustlessness (and you start trusting entities telling you whether you should, or shouldn't, accept a payment - with all the danger of those entities actually being the ones trying to scam you) or on decentralisation and permissionlessness (even if those trusted entities are to be trusted, they are single points of failure whose role you couldn't just, on your own decision, not take over).

In fact, you'd end up with a system that looks a lot like the current fiat system, with a lot of cross checks, reporting, auditing etc... even though it might be somewhat automated cryptographically.

Essentially, if you think that users should have their account at some or other "delegated node of trust", that's nothing else but the banking office where these users have their account, in a way.  If these entities decide to tell you that owner X has nothing in his account, then you will not trust owner X's transactions, even though he may have stuff in his account, but his "node of trust" to which his account was delegated, decided to punish him for one or another reason...

But that's part of crypto.  In my mind, crypto gets its value from the megalomania of the project it carries.  Bitcoin was already a totally deluded idea: "replace money world wide".   How can you beat such a deluded mega-projection ?  Well, ethereum is going to replace all law, judges, lawyers contracts and agreements world wide, (and yes, as a side effect, can also replace that small thing, money, if it wanted to).

If you want people to throw value at a token that doesn't mean, in itself, anything, you need irrational exhuberance, and you have to promise something mindbogglingly great.  "replacing money" sounded big.  Replacing law and contract, sounds bigger.  The bigger, and the more deluded, the better. 

But the next delusion is already in the making in crypto: "replacing social contacts" and "replacing knowledge". 

I guess the next layer, after that, is: "replacing life".