The vulnerability is that one can make bitcoin unusable and centralized through a very low cost attack vector if the block size is increased.

I wouldn't mind large blocks (even 20mb) if there was an adequate fee structure in place that prevents abuse.

Let's say I'm the US government and want to shut down BTC... what kind of attack vectors do I have?

Some examples:

a) Built an expensive NSA farm to get the 51%. Doable but it will cost me a few hundred millions. The reward would be to wipe off competition for the USD.
b) Bribe or hack centralized mining systems that tend to have lots of hashpower.
c) Coordinate attacks that allow a 51% attack to go through by preventing others from hashing.
d) Start stealing people's private keys through the use of monitor equipment in people's hardware (that would 'burn' that option from future use, and make it publicly known)
e) Make various DDOS / DOS attacks that have low cost
f) Bloat BTC to infinity, if BTC allows itself to be bloated in this way (and it will with large blocks), again at very low cost. Thus it will become difficult to download, adoption will be hampered and you get it to a much more centralized and vulnerable point.
g) Accumulate or confiscate stashes of BTC to manipulate price and through market manipulation, destroy the BTC market. You can also "use" various exchange owners after they get an offer they cannot refuse ("please cooperate or else you'll be thrown in jail for decades with charges of assisting money laundering").
h) Do mass damage to unsuspecting people and then claim it's BTC's fault, so you need to ban it. Stuff like mass hacking of PCs, encrypting their data and blackmailing people. Or media attacks, association with criminal activities etc etc.
i) Ban it, but then it will flourish elsewhere. So you pressure various governments to do the same. But, that too, shows desperation and panic so it's better not to ban it and go more "subtly" about it (GOTO other attack vectors).

- stuff like that.

(f) is an avoidable attack vector.

Multiple blockchains do not reduce bloat on aggregate, they multiply it. However, you only download the blockchains you want. You are not forced to use 1000 blockchains if there are 1000 altcoins. You only download and use those that you like.

Just because one hard disk doesn't fit the world's data it doesn't mean that hard disk drive was a useless invention.

We can still use multiple hard disks, even with their finite capacity limits.

Likewise, we can use multiple blockchains to store transactions and other stuff.



Historically it was. This can't be disputed really.

Gold = high denomination coins
Silver = medium
Copper = small

Bitcoin, as a protocol, can do that. But it doesn't need to be ONE chain for everything.

Bloat always makes the situation worse.


Not for Bitcoin the protocol, but Bitcoin as in BTC, the currency, the BTC blockchain etc.

Gold was currency.
Silver was currency.
Copper was currency.

They were in circulation simultaneously. Why didn't they only have gold or silver coins? Because each thing served a different need.

If transactions go up significantly, there is no problem in having spillover of microtransactions into bitcoin-based altcoins. Faster, cheaper and their blockchain is a far less valuable resource that can be ...discarded in the long run if it bloats to unusable levels.


The protocol exists for all this world of opportunities. People can still use an alternate chain if they want to use the blockchain to store data, contracts, intellectual property etc etc. There is no "necessity" that it must be done on BTC's blockchain. And it won't be some kind of failure if everything doesn't fit in the BTC blockchain.

So in real life you have multiple payment systems for different purposes, with multi-tiered costs, speeds etc.

In Bitcoin you want to make from microtransactions to billion $$$ transactions, in the same way, with the same speed, with the same minimal cost. Ah well, give it some time until it gets there, right now it clearly isn't capable to scale to that level. And it won't be by doubling or quadrupling, or 1000x the block size. You can't scale such a system to the degree that hierarchical systems do, but other problems plaguing hierarchical systems are dealt with. It's a balancing act.

And downloading terabytes of blockchain bloat will?

Bitcoin is a protocol and while it is true that scaling issues exist, they are being worked on to find solutions. But nobody says we all have to use just one blockchain for storing everything, and doing so with zero cost. This is not feasible. We can transact with Dogecoins for the lulz if we want to. It's still bitcoin-based tech. You can have 100 chains, or 1000 chains. The sky is the limit.

As for cost: In Greece, in order to conduct a bank wire from one bank acc of bank A to another bank account of bank B, it goes like cost 1 euro for sender, cost 3 euro for receiver. Total 4 euros of charge even if I transfer like 10 euros. Do you think this puts people off from transacting with the banks? No. They just don't do it for small amounts, or if they do they are using something like "offchain" transaction by using the same bank for internal transferring of one bank account to the other, which typically has zero cost.

We have different interpretations of stupidity.

When I have a system that has a hole in it (bloat in blockchain through low or no fees, that can be abused as an attack vector and kill bitcoin usage and adoption in the long run), I will not go and make it larger so that someone else can sink my boat. *That* is stupidity.

Scaling is not an issue right now. Not the processing of transactions. If you want to make a legitimate transaction, you'll pay a normal fee and you'll be processed in one block.

If you enlarge the block before scaling becomes an issue, then you open the attack vector wide open for further abuse (because it is already abused with over half the transactions being dust and spam). This is beyond idiotic.

I believe when the time comes, and the need is real, the block size can be increased. If it doesn't, there will be just some fee competition that prevents a lot of low and very low value tx. So what? This is certainly the lesser of the two evils involved here.

Sounds like it will finally work like it should be.

The blockchain is too valuable a resource to be wasted by zero and ridiculously low fee txs.

And it's not only scaling but usability too. If I have a 100mb block size and it takes me a couple of hours just to sync the last day or a day to sync the last week (before I send a payment), will this be usable? Or will people say, ah yes, now you lost the ability to run bitcoin-qt, just use a thin client...

That's where the chain breaks.

Expensive is a relative term compared to your competition.

How much does a bank charge for an international bank wire?

If BTC costs < Western Union costs, Bank costs, etc = adoption continues to grow because your competition is still much more expensive than you. The money transfer industry won't go to zero fees overnight to compete with BTC.

Restricted space => creates fee competition => dust will become non-economically viable to move around.

So you have a policy right there. It doesn't yet work because blocks are half-full (~500kb on average) so you can still move dust with near zero cost (if you have the patience to wait), but the policy will work when legitimate transactions increase in volume to approach the block size limit. We are not there yet.

There is no "artificial limitation on everybody". Those who pay a competitive fee are included next block, even if the block size is ...100kb.

The quality of saturation is the critical element one should be worried about.

Saturation from dust, spam, worthless micro-txs, faucets, dice, "stress tests", scripts that are purposefully wasting space in the blockchain for minimal fees, etc = nobody should even bother.

Saturation from legit txs should get a bump to accommodate for new capacity.

If you enlarge the block size prior to being genuinely saturated, you are just opening the bloat-attack-vector, wide open. And then users will say 'ohhh, this is bullshit, this program BTC requires me to download 2 tb of data prior to using it"... or, if someone is in a country where bandwidth is expensive and they are charged for over-the-top use, after, say, 100gb/month, "aaah, I can't even sync this without going over my monthly quota". Or "shit, I have to send these money out, and I'm syncing the last 30 hours and it takes an hour to do so"... because 8mb blocks are full of cheap spam and dust.

If someone says "but we can send these users to thin clients, web wallets etc", just contemplate that if this happens now, and having your own bitcoin-qt is unsustainable for a lot of people, then what will happen in 5 years or 10 years?

Block size needs a glide path that co-incides with actual usage, and marginalizes spam/dust, or makes it expensive for such txs.

I'm quite a bit souther than alex-ru... (GR)eece.

"Noted scammer Evan Duffield"? http://www.newsbtc.com/2015/01/11/darkcoin-dev-evan-duffield-wins-proof-honor-award/

"Public outcry" the 5 Monero trolls and their sockpuppets, who spend day and night in this thread trolling?

And that's exactly my point. You have to mix with something other than your own and when you do that you are potentially vulnerable (with the probabilities being from very low, to very high, depending other parameters).

...and that's possible because (simplistically speaking) you are mixing with others, and if they have a lot, they can single you out. No?

Let's say tomorrow I start using Bytecoin / BCN for my anonymous transactions.

Explain to me why Bytecoin is vulnerable from deanonymizing my transactions by those who have like 87% of the coins. What type of mechanism is there in place that deanonymizes me, and isn't the same mechanism there for Monero as well - even if the 87% stealthmine is not?

If you are mixing, you are always mixing with someone else. And he can single you out (sybil attack).

You can improve that (possibility of remaining anonymous) by increasing the mixing number, number of times you mix your coins etc. But there is always someone else (real or virtual) involved.

But since high mixing creates some very sizable bloat which prevents the coin from being usable, the default level is pretty low in those "other coins". So, take my suggestion and instead of being in the Dash thread all day along with the other resident trolls, go to the XMR thread and ask your devs to make XMR scale to a usable level. XMR has to improve and become something more than an unusable proof-of-concept - although, to be honest, I doubt this can be done with the available technology. In any case, Dash needs better competition to improve itself further.

https://bitcointalk.org/index.php?topic=421615.msg6815040#msg6815040 => "I have 2 possible solutions to evaluate for V2 of darksend (ring signatures and encrypted system where the users themselves do the joining relayed through the masternodes.) . Both of these make the masternodes unaware of who is sending money to whom, so centralization isn't an issue at that point."
https://bitcointalk.org/index.php?topic=421615.msg6862900#msg6862900
https://bitcointalk.org/index.php?topic=421615.msg6864666#msg6864666

As for "proof", well Bitcoin as it is can't scale. It'd need petabytes to compete with payment systems like VISA. You think a coin that generates multiple bloat per transaction, can?

The ring signatures V2, has a follow-up post which has been conveniently omitted. V1 didn't have the DarkSend that is now implemented, rather something like 3x10 DRK, one round. It was real-time, in the sense that you had to transact (DarkSending money) as you were mixing.

I wrote something to the effect that ring signatures are DOA / they don't scale, and then Evan thought of another way to improve mixing, and V2 came out with premixing (no need to mix when sending, which improved speed massively as the money were ready to get spent), multiple rounds, various denominations etc.

So people did get a much upgraded V2, although through a different implementation.