Mike Hearn, London 2014 [video presentation]

[danielW]

So this kind of simulated network can spoof a payment but can not spoof a block confirmation?

Why is it that they cant spoof a confirmation btw (for a SPV client)?


Anyway, if that is the case, then it does seem like a insignificant issue. And there are probably easier and better ways to solve it.

[prof7bit]

So this kind of simulated network can spoof a payment but can not spoof a block confirmation?

Why is cant they spoof a confirmation btw?


Anyway, if that is the case, then it does seem like a insignificant issue. And there are probably easier and better ways to solve it.

Looks like Mike Hearn wants to solve the double spend problem. Maybe someone should tell him that its already solved.

[Mike Hearn]

So this kind of simulated network can spoof a payment but can not spoof a block confirmation?

Why is it that they cant spoof a confirmation btw (for a SPV client)?

Because SPV clients check the block chain.

The problem is that blocks arrive unpredictably. It's not uncommon for there to be an hours wait before the next block. So for many practical scenarios the block chain is not good enough (you still need it, but it's just not a total solution).

Note that the wifi hacking attacks can be "solved" using Tor. I put solved in quotes because Tor solves it by being more centralised than Bitcoin is, so whether this is a satisfactory solution is arguable.

You can also solve it by using your 3G connection and trusting your cell carrier, but that's also solving via centralisation. I thought people in this thread hated governments and corporations? Saying "just don't use wifi" seems like a rather statist solution

[prof7bit]

There is only one authority that could ever be allowed to issue stuff like passports or certifications or hold elections and publish the results and this is the block chain!

The Tor project is rewarding long running nodes the "entry guard" status and once a node is elected and promoted to that status its recorded in their golbal consensus. their consensus is a fixed centralized consortium of servers run by the Tor project. We have a global consensus too, if we had the equivalent of "entry guards" it would be recorded in the block chain.

How about this: proof-of-uptime: instead of proving a sacrifice how about rewarding long running nodes or nodes that have relayed a lot of transactions for a long time with colored Satoshis to a dedicated address of this node. Upon connect the node would would sign a response to a challenge with this key/address and the other node can then look up the "trust"-level and the age of this address in the block chain.

This is only an idea. It still has to be refined, for example the SPV client needs to query all these proof-of-uptime tx for a new node (and check them against the block headers) if it has not yet seen this same node before, etc. but this is the general way I would like to see such kinds of problems be approached and not the cheap way of asking a central authority to do it for us. If we wanted a central authority we could ask the foundation to run a server for us and would not need the block chain anymore at all. Then we would have invented PayPal.org.

We are making a lot of propaganda of how useful a global decentralized trustworthy ledger is and how all kinds of important stuff can be recorded and certified there because we have finally solved the consensus problem and now we have something important that needs to be recorded or certified in a secure and trustworthy manner and the first thing Mike comes up with is invoking the government to do it for us instead of using our own cool new technology of global consensus.

[waxwing]

You can also solve it by using your 3G connection and trusting your cell carrier, but that's also solving via centralisation. I thought people in this thread hated governments and corporations? Saying "just don't use wifi" seems like a rather statist solution

There are two reasons that kind of centralisation doesn't bother me - (1) the trusted third party is impartial and (2) it's still distributed as one can use any one of a number of parties, different ISPs, networks, or use websites or nodes with ssl certificates to do the same job of giving a trustworthy report. It's (2) that's most important of course, because without the distribution, trusting one party gives them too much power and then (1) wouldn't really apply anymore.

As a concrete example I would, for now, trust blockchain.info over https to report the existence of an unconfirmed payment, acting as a cross check against whatever my client is telling me.

[porcupine87]

Hm and to get a trusted node, could we not just use the they key point of Bitcoin itself? A node, that relayed a certain amount of blocks the last 24hours (or maybe month), is not a made up node. Noone can just make up such nodes out of the thin air.

Or would it be some kind of DDOS when everybody connects to the same node?

The last 4 days there where 111 different IP addresses which relayed a solved block. Would that be enough for such special cases like buying a bitcoin with local bitcoin and going out with zero confirmation?

[Mike Hearn]

Yes, obviously having a trusted node solves the issue as well, which is why b.i and Electrum aren't so vulnerable to this attack. They trade off centralisation against having no sybil attacks.

Re: proof of uptime. The question is what measures the uptime. A wallet can reconnect to nodes it used before (it can become "sticky") if they seem to be long term nodes, but this requires care.

Firstly it'd require giving each node a long term key so connections can be authenticated. We talked about using SSL (without certificates) between P2P nodes and I still like that idea, but Gregory pointed out that OpenSSL is huge and complicated and people worry about exploits. Tor for SPV avoids that problem because it's all pure Java and just client code anyway. We could do an ad-hoc Bitcoin specific authentication solution though.

Secondly we'd have to be careful about load balancing. Right now SPV wallets get sprayed across the network by the DNS seeds. If wallets kept reconnecting to nodes they used before because they were long-term and therefore more likely to be good, you could end up with wild load imbalances. Tor has some experience with this.

Thirdly, we have the question of what you do if you can't reach your preferred long term nodes. If you try to connect and they aren't there anymore, you can easily go find new nodes .... but now you're back to having a sybil attack.

These problems are really hard. Remember that the "zero knowledge proof of passport" idea doesn't rely on uploading or publishing your actual passport data/identity anywhere. You provide a mathematical proof that you have a passport, but that doesn't give anything away by itself (billions of people have passports).

[zunath]

This guy scares the hell out of me.

[lucaso]

I don't see anything revolutionary here. Who cares about such "passports" it just won't work, idea is not bad, but implementation is impossible in current environment.

There are many ideas around so don't panic please, many more will appear.

Furthermore speech about security was mostly ok (especially mobile wallets and Wifi), but Mike ideas are not final and I don't feel that he is able to force them against our will. So please don't make any personal attacks here it's childish.

[NanoAkron]

You can also solve it by using your 3G connection and trusting your cell carrier, but that's also solving via centralisation. I thought people in this thread hated governments and corporations? Saying "just don't use wifi" seems like a rather statist solution

There are two reasons that kind of centralisation doesn't bother me - (1) the trusted third party is impartial and (2) it's still distributed as one can use any one of a number of parties, different ISPs, networks, or use websites or nodes with ssl certificates to do the same job of giving a trustworthy report. It's (2) that's most important of course, because without the distribution, trusting one party gives them too much power and then (1) wouldn't really apply anymore.

As a concrete example I would, for now, trust blockchain.info over https to report the existence of an unconfirmed payment, acting as a cross check against whatever my client is telling me.

Centralisation is diametrically opposed to the central ideology of the zero-trust, distributed nature of bitcoin. Trusting any third party now is a slippery slope to further centralisation and control later.

[MarketNeutral]

So this kind of simulated network can spoof a payment but can not spoof a block confirmation?

Why is it that they cant spoof a confirmation btw (for a SPV client)?

Because SPV clients check the block chain.

The problem is that blocks arrive unpredictably. It's not uncommon for there to be an hours wait before the next block. So for many practical scenarios the block chain is not good enough (you still need it, but it's just not a total solution).

Note that the wifi hacking attacks can be "solved" using Tor. I put solved in quotes because Tor solves it by being more centralised than Bitcoin is, so whether this is a satisfactory solution is arguable.

You can also solve it by using your 3G connection and trusting your cell carrier, but that's also solving via centralisation. I thought people in this thread hated governments and corporations? Saying "just don't use wifi" seems like a rather statist solution

Don't put words in our mouths. I object to the heedless abandon with which you propose solutions to what you perceive to be bitcoin's problems with blatant disregard for the opinions of the wider bitcoin user base and the spirit of freedom upon which bitcoin was founded. You seem to want to turn bitcoin into a draconian, quasi-paypal system. Your vision of bitcoin's future seems antithetical to the whole purpose of bitcoin.

I understand that bitcoin needs to evolve from Satoshi's original client. Yet to myself and many of us, your "solutions" follow the same trajectory of hubris, folly, and greed from which many of us are attempting to distance ourselves by using bitcoin in the first place. Might as well go back to SWIFT, paypal, and visa/mastercard.

Mike, you have some serious explaining to do.

When we talk of centralization, we're not necessarily talking about 3G or Tor. Yeah, such aspects need to be addressed, but don't miss our point. We're talking about your proposed blacklisting and passport ideas. i.e., Censorship or the means to enact it, and letting other people have more and unnecessary control over our money. Why should anyone but me get to decide whom I can transact with?Bitcoin is a powerful tool that greatly promotes self-reliance and people "being their own bank." People see this, they love it, and they feel you're attempting to take this newfound freedom away from them.

Moreover and to the point, centralization creates weakness by having a more centralized point of failure.

[NanoAkron]

MarketNeutral - thank you for putting that into words.

Mike, if you believe 'billions of people have passports', you're very misinformed. Fewer than 50% of the Japanese and US populations hold passports - two of the largest economies in the world.

You push this need for an external token, which goes against the core values of bitcoin. If you can't come up with a solution that is in keeping with the ideals of bitcoin then I'd rather you didn't propose one at all.

Your answer had better not be along the lines of 'you don't understand' or 'it's only optional' or 'well why don't you code it then'.

[erik777]

This idea should be dead in the water because it is based on Mike's assumption that everyone has a passport.  In America, only 30% of people have a passport.  I imagine it is lower in many other countries, and higher in some, such as where Mike is from.  

What baffles me is that he's been studying the passport idea for 6 months, but it only takes 5 minutes to Google up the low percent of people using passports.  Unfortunately, Google, Yahoo and Bing will only give me American statistics -- whether bias on their part or lack of info elsewhere IDK.  But, still.  

Shall all nodes be concentrated in the UK or wherever passport use is high, and be limited in countries where passport ownership is very low?  

I'm against this for many reasons.  But, I'd think that the low rate of passport owners would be enough to kill it without 6 months of analysis and code being written.  What concerns me is that this logic hasn't killed this idea, yet.  

I guess that Mike thinks that 2/3 of Americans live in Iowa.  

CNN
Forbes

For those outside the US who wonder why only 30% of Americans have passports, besides the high cost of travelling across the ocean, most Americans are lucky if they can see half the wonders of America before they die.  Also, before 9/11, US citizens didn't need a passport to travel to Canada or Mexico. 
 

[btcash]

Too bad he said nothing about reducing/trimming the blockchain size.

The Payment Protocol to replace addresses. Supports refunds, memos, receipts, proof-of-purchase, and digital signature.

Instead he talks about bloating the blockchain even more. Maybe I missed something but with these feature not only miners can easily include child pornographie into the blockchain but also every normal user? Why is this not an issue?

And what is with all the sybil talk?

That's actually a very hard attack to successfully pull off; I file it under "theoretically worrisome, but practically not a high priority."

But I like the idea of Proof of Sacrifice.

[prezbo]

This idea should be dead in the water because it is based on Mike's assumption that everyone has a passport.  In America, only 30% of people have a passport.  I imagine it is lower in many other countries, and higher in some, such as where Mike is from.  

What baffles me is that he's been studying the passport idea for 6 months, but it only takes 5 minutes to Google up the low percent of people using passports.  Unfortunately, Google, Yahoo and Bing will only give me American statistics -- whether bias on their part or lack of info elsewhere IDK.  But, still.  

Shall all nodes be concentrated in the UK or wherever passport use is high, and be limited in countries where passport ownership is very low?  

I'm against this for many reasons.  But, I'd think that the low rate of passport owners would be enough to kill it without 6 months of analysis and code being written.  What concerns me is that this logic hasn't killed this idea, yet.  

I guess that Mike thinks that 2/3 of Americans live in Iowa.  

CNN
Forbes

For those outside the US who wonder why only 30% of Americans have passports, besides the high cost of travelling across the ocean, most Americans are lucky if they can see half the wonders of America before they die.  Also, before 9/11, US citizens didn't need a passport to travel to Canada or Mexico.  

Again, I think you misunderstood the whole concept. Having a passport is not a requirement, but if I am using an spv wallet, I'd like to connect to someone that is authenticated using a passport so I know I'm not being a victim of a sybil attack. For this system to work only a minority actually needs to run such a node.

I, for one, am grateful someone is thinking outside the box. Nobody said this is the best possible solution but it's a step forward in solving a problem.

[NanoAkron]

This idea should be dead in the water because it is based on Mike's assumption that everyone has a passport.  In America, only 30% of people have a passport.  I imagine it is lower in many other countries, and higher in some, such as where Mike is from.  

What baffles me is that he's been studying the passport idea for 6 months, but it only takes 5 minutes to Google up the low percent of people using passports.  Unfortunately, Google, Yahoo and Bing will only give me American statistics -- whether bias on their part or lack of info elsewhere IDK.  But, still.  

Shall all nodes be concentrated in the UK or wherever passport use is high, and be limited in countries where passport ownership is very low?  

I'm against this for many reasons.  But, I'd think that the low rate of passport owners would be enough to kill it without 6 months of analysis and code being written.  What concerns me is that this logic hasn't killed this idea, yet.  

I guess that Mike thinks that 2/3 of Americans live in Iowa.  

CNN
Forbes

For those outside the US who wonder why only 30% of Americans have passports, besides the high cost of travelling across the ocean, most Americans are lucky if they can see half the wonders of America before they die.  Also, before 9/11, US citizens didn't need a passport to travel to Canada or Mexico.  

Again, I think you misunderstood the whole concept. Having a passport is not a requirement, but if I am using an spv wallet, I'd like to connect to someone that is authenticated using a passport so I know I'm not being a victim of a sybil attack. For this system to work only a minority actually needs to run such a node.

I, for one, am grateful someone is thinking outside the box. Nobody said this is the best possible solution but it's a step forward in solving a problem.

And what happens when we decide that people with Zimbabwean passports, or Venezuelan ones, or Gambian ones, or Tibetan ones, are just not allowed to run nodes anymore?

ANY centralisation or requirement for a centrally-issued external token is risk that we're beginning down a slippery slope towards blacklisting or worse.

[erik777]

This idea should be dead in the water because it is based on Mike's assumption that everyone has a passport.  In America, only 30% of people have a passport.  I imagine it is lower in many other countries, and higher in some, such as where Mike is from.  

What baffles me is that he's been studying the passport idea for 6 months, but it only takes 5 minutes to Google up the low percent of people using passports.  Unfortunately, Google, Yahoo and Bing will only give me American statistics -- whether bias on their part or lack of info elsewhere IDK.  But, still.  

Shall all nodes be concentrated in the UK or wherever passport use is high, and be limited in countries where passport ownership is very low?  

I'm against this for many reasons.  But, I'd think that the low rate of passport owners would be enough to kill it without 6 months of analysis and code being written.  What concerns me is that this logic hasn't killed this idea, yet.  

I guess that Mike thinks that 2/3 of Americans live in Iowa.  

CNN
Forbes

For those outside the US who wonder why only 30% of Americans have passports, besides the high cost of travelling across the ocean, most Americans are lucky if they can see half the wonders of America before they die.  Also, before 9/11, US citizens didn't need a passport to travel to Canada or Mexico.  

Again, I think you misunderstood the whole concept. Having a passport is not a requirement, but if I am using an spv wallet, I'd like to connect to someone that is authenticated using a passport so I know I'm not being a victim of a sybil attack. For this system to work only a minority actually needs to run such a node.

I, for one, am grateful someone is thinking outside the box. Nobody said this is the best possible solution but it's a step forward in solving a problem.

And what happens when we decide that people with Zimbabwean passports, or Venezuelan ones, or Gambian ones, or Tibetan ones, are just not allowed to run nodes anymore?

ANY centralisation or requirement for a centrally-issued external token is risk that we're beginning down a slippery slope towards blacklisting or worse.

Yeah, I agree.  At a minimum, it's discriminatory against those who don't have a passport, which is dividing the bitcoin community up.  Bitcoin needs to remain a trustless network.

In addition to Mike clearly incorrectly assuming that everyone outside Iowa has a passport, his proposal is based on other assumptions that are just false:

Ass. 1> Only the government has access to the database.  

He's ignoring how easy it is to collect this data with an RFID reader by just hanging out at an airport.

Ass. 2> People only have 2 or 3 passports, limiting their ability to fake many nodes.

Honest people with iPhones will be limited to 2 or 3 passports.  Referring to #1, people with RFID readers or NFC equipped Android phones can have thousands -- and they are likely to be in the dishonest category, the same people who would simulate a network.  

Ass. 3> Governments can be trusted.  

Is anyone outside the US reading about how the NSA deliberately weakening encryption at the RSA? And how one man walked out with nearly all the US Government's best kept secrets from the most protected division of the world's strongest military?  

  

[tvbcof]

...
I understand that bitcoin needs to evolve from Satoshi's original client. Yet to myself and many of us, your "solutions" follow the same trajectory of hubris, folly, and greed from which many of us are attempting to distance ourselves by using bitcoin in the first place. Might as well go back to SWIFT, paypal, and visa/mastercard.
...

This seems to be a basic assumption that everyone from the most fresh newbie to Gavin takes as gospel.

I say, 'not so fast'.  The basic structure of the original implementation (which we are still in) has proven pretty useful, and I don't think it can be written off as being valuable due simply to future expectations.  I think it is useful and trusted because it is still difficult to assault, and this because the stand-alone core infrastructure is operable in a very widely distributed manner.

A series of 'off chain' solutions (like BitPay, Coinbase, Mt. Gox, vendors like TigerDirect, etc) riding on the back of what we have currently has the potential to scale.  It would be 'SWIFT, paypal, and visa/mastercard' but for one very unique difference:  The core value store would not be under centralized control.  And people could still keep their lifes' savings in a paper wallet if the so choose.

Moreover and to the point, centralization creates weakness by having a more centralized point of failure.

There is room for a lot of 'centralization' at the second tier level where individual failures do not threaten the entire system.  BTCChina is a wonderful example of this principle.

[Carlton Banks]

This is a very specific proposed use of the bitcoin ID protocol, government passports are not required if you don't want to use them. Mike's just advocating a state dependent usage in the way you'd expect him to, but the base technology for this is equally good for stateless ID's too. In fact, it gives you the ability to create a form of ID that's less corruptible than any state run scheme. And you can choose how you structure it for yourself, and others can accept that as valid as they choose (but hopefully on some basis of how well it identifies you in an objective way  )

[waxwing]

Question for Mike or anyone else who knows about this stuff:

What about a scenario brought up by a reddit user: a hotel clerk in a tourist destination handles a hundred international passports in a day. Is there some way they can surreptitiously grab a signature from each of them and use them for an attack?
So I tried an app out with my phone and it read the biometric,photo and ID details fine. The security info says the signatures are OK but it seems there is no "Active Authentication", meaning the passport could be cloned. Apparently that's the common situation according to this.

Without active authentication the system won't be defended against the hotel clerk attack, is that correct (because there is no nonce provided from the reader)?