8 ms·

Blockchain Is Puny

29 points by elsewhen 5y ago

chris_wot 5y ago
I’m still trying to understand why it is so evil that a centralised authority controls a transaction ledger. Why, exactly, is this a bad thing?
- wyck 5y ago
  "so evil that a centralised authority controls", repeat your own sentence a few times.
  - chris_wot 5y ago
    I by and large think the Reserve Bank if Australia is benign.
- jMyles 5y ago
  Among the many reasons: because they can censor the ledger to make it impossible for you to pay for the vegetables you prefer to smoke.
  - andai 5y ago
    Or shut off your PayPal, or block your business from taking credit cards, because they personally find your business unsavory, and soon you won't be able to take cash because there's a worldwide push to get rid of it, and many other reasons.
    - rantwasp 5y ago
      lol Paypal: https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full You may not use the PayPal service for activities that: * violate any law, statute, ordinance or regulation. * relate to transactions involving (a) narcotics, steroids, certain controlled substances or other products that present a risk to consumer safety, (b) drug paraphernalia, (c) cigarettes, (d) items that encourage, promote, facilitate or instruct others to engage in illegal activity, (e) stolen goods including digital and virtual goods, (f) the promotion of hate, violence, racial or other forms of intolerance that is discriminatory or the financial exploitation of a crime, (g) items that are considered obscene, (h) items that infringe or violate any copyright, trademark, right of publicity or privacy or any other proprietary right under the laws of any jurisdiction, (i) certain sexually oriented materials or services, (j) ammunition, firearms, or certain firearm parts or accessories, or (k) certain weapons or knives regulated under applicable law. * relate to transactions that (a) show the personal information of third parties in violation of applicable law, (b) support pyramid or ponzi schemes, matrix programs, other "get rich quick" schemes or certain multi-level marketing programs, (c) are associated with purchases of annuities or lottery contracts, lay-away systems, off-shore banking or transactions to finance or refinance debts funded by a credit card, (d) are for the sale of certain items before the seller has control or possession of the item, (e) are by payment processors to collect payments on behalf of merchants, (f) are associated with the sale of traveler's checks or money orders, (g) involve currency exchanges or check cashing businesses, (h) involve certain credit repair, debt settlement services, credit transactions or insurance activities, or (i) involve offering or receiving payments for the purpose of bribery or corruption. * involve the sales of products or services identified by government agencies to have a high likelihood of being fraudulent. Look at what you need approval for: https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full
  - AndrewUnmuted 5y ago
    How's PorcFest going?
    - jMyles 5y ago
      Oh, it's so absolutely lovely. (Do we know each other? Or did you just read somewhere that I was going? Or just divine it from comments?) Although this is my 4th, I haven't been to the last seven in a row. From 2014 to 2021, it has changed substantially in some ways (many more women and people of color, for example) and stayed almost identical in others (feral children starting businesses to be able to buy toys and ice cream, etc). This is the first time I've had the bus, so we have a little more creature comfort than before. Have you been before? I highly, highly recommend it. Hard to find a place to surround yourself with a higher concentration of loving / accepting energy.
- babaganoosh89 5y ago
  It's as evil as you think the centralized authority is now or will be in the future. Some will also argue any entity having complete power over your life is inherently evil.
- jayd16 5y ago
  Its not. We use federated authorities and chains of trust all over the place. But now its actually possible to have a distributed ledger so we're searching for problems to solve with this solution.
  - rantwasp 5y ago
    sure thing. we have invented something and now we are trying to apply it /s how did the authorities and the chains of trust emerge in the first place? Is a system that uses a central authority more or less stable than a system that does not rely on the said authority?
    - jayd16 5y ago
      Most consumer safety/encryption uses some kind of certificate chain with trusted roots. Its used from app installs to SSL to credit transactions. Seems to be very efficient, cheap and effective.
      - rantwasp 5y ago
        nah. you're talking the tech. I'm talking about the actual authority. What if someone decided that they would not issues you a cert? How would you do business at that point? But it's so efficient you says... Also, it's efficient up to the point where you have to revoke a certificate. At that point the fun starts.
- rantwasp 5y ago
  when you understand that a centralized authority decides what is okay and what is not okay and after that bans transactions that pay for the "not okay" items you will understand why a centralized authority is evil. The magic keywords are "Prohibited Products and Services" Plug that into google + your favorite payment gateway. Here are some samples: https://www.nextpay.com/list-prohibited-industries.html https://www.nextpay.com/list-prohibited-industries.html https://stripe.com/restricted-businesses https://stripe.com/restricted-businesses https://support.wix.com/en/article/wix-payments-prohibited-products-and-services https://support.wix.com/en/article/wix-payments-prohibited-p... http://support.worldpay.com/support/kb/gg/billdesk/content/prohibitedmerchantcategories.htm http://support.worldpay.com/support/kb/gg/billdesk/content/p...
  - grey-area 5y ago
    The problem with this argument is that governments still have jurisdiction over your decentralised blockchain, the developers, the miners, and anyone else involved in it. If you sincerely and seriously want to dismantle that power structure, that's fine, but please start in the right place, with government. It's naive and ultimately fruitless to throw out all the good things that centralised payments bring (fast transactions, fraud control, etc etc) in the hope that you'll be able to get rid of a thing they don't actually have ultimate jurisdiction over (what is ok and not ok to buy).
    - rantwasp 5y ago
      yes, but no. how would enforcing such jurisdiction even look like? you cannot take something off the blockchain. Can you shutdown miners? sure. So what? The mining will happens somewhere else. Can you really prohibit developers from working on the tech? If it comes down to this we're in full anarchy mode (and even at that point there are going to be people working on it). Who said anything about throwing away all the good things centralized payments bring? How about we take a decentralized payments system and actually add those things (or even better, build a system that has them out of the box)
      - Retric 5y ago
- kovek 5y ago
  When pornhub wanted to start working with Visa, they had to shut down all pornhub non-verified accounts. Visa's terms.
  - mattzito 5y ago
    As I recall, the issue was that it turned out that a lot of underage and non-consenting people were in videos on pornhub, and then MasterCard/visa said they would pull their support unless they fixed it.
- cmckn 5y ago
  I think a legitimate downside to blockchain is privacy. Sure, Stripe can (try to) prevent you from buying marijuana, but with crypto you’re required to announce that you’ve bought something from Dr. Chronic on the public ledger. Doesn’t that create an opportunity for discrimination/censorship/prosecution post-purchase? At least with Visa, you have a reasonable expectation that the transaction is private between you and the merchant. If you actually made the majority of your purchases on a blockchain, you’re publicizing a ton of information about yourself.
  - uncomputation 5y ago
    I have the same question. Usually the response is something about using randomly generated IDs/addresses with your “wallet” program managing all these pseudonyms and tying them to your actual identity for your convenience, but I don’t understand how that is any better than our current system where things just are private by nature. I don’t expect people to be okay with their purchase histories being public knowledge.
    - deleted 5y ago
      [deleted]
    - bruce343434 5y ago
      Monero solves this with cryptographic methods which are beyond me. But it works. Bitcoin indeed not so much - as soon as you can link a bitcoin address to somebody's identity it's over for them.
  - ashishmax31 5y ago
    I'm no expert in crypto. But how would people know that your public key belongs to "you" ?
    - deleted 5y ago
      [deleted]
    - rwbhn 5y ago
      The other party in any transaction knows enough to "deliver" whatever you purchased. In the world where all your transactions happen on a blockchain, that's everyone from Amazon to the corner pizza shop.
- 6gvONxR4sf7o 5y ago
  It only seems like a problem to me in a monopolistic setting. If it's easy to go from visa to mastercard to your bank's debit card to venmo and easy for newcomers to enter, I don't see the problem. It's a big if :(
- gpsx 5y ago
  A central authority means not only trust but responsibility, and in turn risk. Why require so much responsibility when it is not necessary? The possible problems are not only malicious actions from the central authority but accidental actions and also susceptibility to malicious third parties. [Edit - problems]
milansuk 5y ago
I don't know much about STARKs, but I read that SNARKs has a problem with unbounded loops(variable number of iterations), also "break/continue" statements are problematic. Is it still true? Is there some research that will allow running code as is(no inefficient tricks like running maximum possible iterations)?
- tromp 5y ago
  You can think of STARKS/SNARKS as proving computation, not by a program, but by a computational circuit. So the circuit size puts limits on the amount of computation. Recently, we see the introduction of recursive proof schemes (such as [1]), where part of the circuit may be verifying a proof of a much larger computation. Those can deal with certain forms of unbounded computation, such as verifying a blockchain history of arbitrarily many blocks. [1] https://eprint.iacr.org/2021/370.pdf https://eprint.iacr.org/2021/370.pdf
- jl2718 5y ago
  No. This would be a tautological violation of zero-knowledge, so it will never be solved. However, if all you care about is the verification proof, then yes, you can prove arbitrary recursions by providing the branch condition evaluations as part of the proof.
ianbicking 5y ago
Kind of an aside, but as the post talks about all the work needed to be done to verify additions to the blockchain, that also implies people could be adding invalid content to the blockchain. Usually invalid stuff is easier to confirm than valid, but still, how easy is it to use invalid additions to spam the chain? Do valid transactions get validated on top of invalid transactions and require revalidation? Or is the initiator of the transaction responsible for recreating on a valid basis? I'm sure this is all basic blockchain stuff but it hadn't occurred to me before...
- sleavey 5y ago
  The "proof" part of proof of work used by Bitcoin is a small piece of information that proves that a lot of work has been done. An invalid proof can be easily checked by other nodes and ignored. In the case of Bitcoin the proof is a set of alphanumeric characters as input to the hashing algorithm (SHA256 I think) that produces a hash with certain properties (some number of leading zeros depending on the current difficulty). Other nodes can verify the proof by taking the input supplied by the miner, combining it with a predetermined nonce and computing the hash and checking that it has the properties required. Computing a single SHA256 is easy compared to figuring out which input to the hash produces a particular output. The next mined block will be appended to the longest valid blockchain the node can see. It's in their interest to append to the one that others will believe, because they get paid the reward only on that chain and thus it only exists in their wallet if others accept it by appending further blocks to it. So generating invalid blocks just doesn't work - they get immediately rejected by other nodes and there is thus no reward. One genuine problem is mining a valid block but adding no transactions to it, to grind transaction throughput to a halt. I think Bitcoin might have some mitigations for this but I don't actually know. If a sufficiently well funded organisation or nation tried to take down Bitcoin this might be the way to do it.
  - alisonkisk 5y ago
    Empty blocks generate less revenue (no transaction fees, only the minig reward) but are slightly easier to create due to small mathematical flaws that let you skip some work if the block you create is empty. So for certain pools it's profitable in aggregate to mine empty blocks.
SubiculumCode 5y ago
There were some interesting tidbits in the article, but the claims of very low TPS in blockchain are a bit out of date, to be honest. Things are changing fast in ethereum, cardano, etc.
- remram 5y ago
  Isn't the usual fix to take transactions off the Blockchain? Similarly to how public key crypto is made faster by encrypting a symmetric key?
  - jl2718 5y ago
    You can’t store a blockchain in a ZK-snark/stark either. You can only verify it. So the transactions take place ‘off the blockchain’ here as well. The difference is that they can be verified no matter where they occurred.
    - remram 5y ago
      What do you mean you can't store it?
      - jl2718 5y ago
        The ‘succinct’ part of the acronym means that the data is not stored in the proof.
- lasc4r 5y ago
  As has been the case for over 5 years.
- SubiculumCode 5y ago
  effing downvoters on blockchain topics. get an effing grip
  - brink 5y ago
    If blockchain advocates didn't come of as so cult-ish, it'd be easier to not down-vote. But most advocates talk like blockchain exists in a vacuum. For example I saw a popular blockchain advocate talking about how the Pokemon company should get into NFT's and you have to wonder why? What advantage would it be to use blockchain over a simple database that the Pokemon company owns? I can think of several disadvantages. But the blockchain advocates keep harping on it whether it makes sense or not because it's financially advantageous for them.

29 points by elsewhen 5y ago

I’m still trying to understand why it is so evil that a centralised authority controls a transaction ledger. Why, exactly, is this a bad thing?

wyck 5y ago
"so evil that a centralised authority controls", repeat your own sentence a few times.
- chris_wot 5y ago
  I by and large think the Reserve Bank if Australia is benign.
jMyles 5y ago
Among the many reasons: because they can censor the ledger to make it impossible for you to pay for the vegetables you prefer to smoke.
- andai 5y ago
  Or shut off your PayPal, or block your business from taking credit cards, because they personally find your business unsavory, and soon you won't be able to take cash because there's a worldwide push to get rid of it, and many other reasons.
  - rantwasp 5y ago
    lol Paypal: https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full You may not use the PayPal service for activities that: * violate any law, statute, ordinance or regulation. * relate to transactions involving (a) narcotics, steroids, certain controlled substances or other products that present a risk to consumer safety, (b) drug paraphernalia, (c) cigarettes, (d) items that encourage, promote, facilitate or instruct others to engage in illegal activity, (e) stolen goods including digital and virtual goods, (f) the promotion of hate, violence, racial or other forms of intolerance that is discriminatory or the financial exploitation of a crime, (g) items that are considered obscene, (h) items that infringe or violate any copyright, trademark, right of publicity or privacy or any other proprietary right under the laws of any jurisdiction, (i) certain sexually oriented materials or services, (j) ammunition, firearms, or certain firearm parts or accessories, or (k) certain weapons or knives regulated under applicable law. * relate to transactions that (a) show the personal information of third parties in violation of applicable law, (b) support pyramid or ponzi schemes, matrix programs, other "get rich quick" schemes or certain multi-level marketing programs, (c) are associated with purchases of annuities or lottery contracts, lay-away systems, off-shore banking or transactions to finance or refinance debts funded by a credit card, (d) are for the sale of certain items before the seller has control or possession of the item, (e) are by payment processors to collect payments on behalf of merchants, (f) are associated with the sale of traveler's checks or money orders, (g) involve currency exchanges or check cashing businesses, (h) involve certain credit repair, debt settlement services, credit transactions or insurance activities, or (i) involve offering or receiving payments for the purpose of bribery or corruption. * involve the sales of products or services identified by government agencies to have a high likelihood of being fraudulent. Look at what you need approval for: https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full https://www.paypal.com/us/webapps/mpp/ua/acceptableuse-full
- AndrewUnmuted 5y ago
  How's PorcFest going?
  - jMyles 5y ago
    Oh, it's so absolutely lovely. (Do we know each other? Or did you just read somewhere that I was going? Or just divine it from comments?) Although this is my 4th, I haven't been to the last seven in a row. From 2014 to 2021, it has changed substantially in some ways (many more women and people of color, for example) and stayed almost identical in others (feral children starting businesses to be able to buy toys and ice cream, etc). This is the first time I've had the bus, so we have a little more creature comfort than before. Have you been before? I highly, highly recommend it. Hard to find a place to surround yourself with a higher concentration of loving / accepting energy.
babaganoosh89 5y ago
It's as evil as you think the centralized authority is now or will be in the future. Some will also argue any entity having complete power over your life is inherently evil.
jayd16 5y ago
Its not. We use federated authorities and chains of trust all over the place. But now its actually possible to have a distributed ledger so we're searching for problems to solve with this solution.
- rantwasp 5y ago
  sure thing. we have invented something and now we are trying to apply it /s how did the authorities and the chains of trust emerge in the first place? Is a system that uses a central authority more or less stable than a system that does not rely on the said authority?
  - jayd16 5y ago
    Most consumer safety/encryption uses some kind of certificate chain with trusted roots. Its used from app installs to SSL to credit transactions. Seems to be very efficient, cheap and effective.
    - rantwasp 5y ago
      nah. you're talking the tech. I'm talking about the actual authority. What if someone decided that they would not issues you a cert? How would you do business at that point? But it's so efficient you says... Also, it's efficient up to the point where you have to revoke a certificate. At that point the fun starts.
rantwasp 5y ago
when you understand that a centralized authority decides what is okay and what is not okay and after that bans transactions that pay for the "not okay" items you will understand why a centralized authority is evil. The magic keywords are "Prohibited Products and Services" Plug that into google + your favorite payment gateway. Here are some samples: https://www.nextpay.com/list-prohibited-industries.html https://www.nextpay.com/list-prohibited-industries.html https://stripe.com/restricted-businesses https://stripe.com/restricted-businesses https://support.wix.com/en/article/wix-payments-prohibited-products-and-services https://support.wix.com/en/article/wix-payments-prohibited-p... http://support.worldpay.com/support/kb/gg/billdesk/content/prohibitedmerchantcategories.htm http://support.worldpay.com/support/kb/gg/billdesk/content/p...
- grey-area 5y ago
  The problem with this argument is that governments still have jurisdiction over your decentralised blockchain, the developers, the miners, and anyone else involved in it. If you sincerely and seriously want to dismantle that power structure, that's fine, but please start in the right place, with government. It's naive and ultimately fruitless to throw out all the good things that centralised payments bring (fast transactions, fraud control, etc etc) in the hope that you'll be able to get rid of a thing they don't actually have ultimate jurisdiction over (what is ok and not ok to buy).
  - rantwasp 5y ago
    yes, but no. how would enforcing such jurisdiction even look like? you cannot take something off the blockchain. Can you shutdown miners? sure. So what? The mining will happens somewhere else. Can you really prohibit developers from working on the tech? If it comes down to this we're in full anarchy mode (and even at that point there are going to be people working on it). Who said anything about throwing away all the good things centralized payments bring? How about we take a decentralized payments system and actually add those things (or even better, build a system that has them out of the box)
    - Retric 5y ago
kovek 5y ago
When pornhub wanted to start working with Visa, they had to shut down all pornhub non-verified accounts. Visa's terms.
- mattzito 5y ago
  As I recall, the issue was that it turned out that a lot of underage and non-consenting people were in videos on pornhub, and then MasterCard/visa said they would pull their support unless they fixed it.
cmckn 5y ago
I think a legitimate downside to blockchain is privacy. Sure, Stripe can (try to) prevent you from buying marijuana, but with crypto you’re required to announce that you’ve bought something from Dr. Chronic on the public ledger. Doesn’t that create an opportunity for discrimination/censorship/prosecution post-purchase? At least with Visa, you have a reasonable expectation that the transaction is private between you and the merchant. If you actually made the majority of your purchases on a blockchain, you’re publicizing a ton of information about yourself.
- uncomputation 5y ago
  I have the same question. Usually the response is something about using randomly generated IDs/addresses with your “wallet” program managing all these pseudonyms and tying them to your actual identity for your convenience, but I don’t understand how that is any better than our current system where things just are private by nature. I don’t expect people to be okay with their purchase histories being public knowledge.
  - deleted 5y ago
    [deleted]
  - bruce343434 5y ago
    Monero solves this with cryptographic methods which are beyond me. But it works. Bitcoin indeed not so much - as soon as you can link a bitcoin address to somebody's identity it's over for them.
- ashishmax31 5y ago
  I'm no expert in crypto. But how would people know that your public key belongs to "you" ?
  - deleted 5y ago
    [deleted]
  - rwbhn 5y ago
    The other party in any transaction knows enough to "deliver" whatever you purchased. In the world where all your transactions happen on a blockchain, that's everyone from Amazon to the corner pizza shop.
6gvONxR4sf7o 5y ago
It only seems like a problem to me in a monopolistic setting. If it's easy to go from visa to mastercard to your bank's debit card to venmo and easy for newcomers to enter, I don't see the problem. It's a big if :(
gpsx 5y ago
A central authority means not only trust but responsibility, and in turn risk. Why require so much responsibility when it is not necessary? The possible problems are not only malicious actions from the central authority but accidental actions and also susceptibility to malicious third parties. [Edit - problems]

milansuk 5y ago

I don't know much about STARKs, but I read that SNARKs has a problem with unbounded loops(variable number of iterations), also "break/continue" statements are problematic. Is it still true? Is there some research that will allow running code as is(no inefficient tricks like running maximum possible iterations)?

tromp 5y ago
You can think of STARKS/SNARKS as proving computation, not by a program, but by a computational circuit. So the circuit size puts limits on the amount of computation. Recently, we see the introduction of recursive proof schemes (such as [1]), where part of the circuit may be verifying a proof of a much larger computation. Those can deal with certain forms of unbounded computation, such as verifying a blockchain history of arbitrarily many blocks. [1] https://eprint.iacr.org/2021/370.pdf https://eprint.iacr.org/2021/370.pdf
jl2718 5y ago
No. This would be a tautological violation of zero-knowledge, so it will never be solved. However, if all you care about is the verification proof, then yes, you can prove arbitrary recursions by providing the branch condition evaluations as part of the proof.

ianbicking 5y ago

Kind of an aside, but as the post talks about all the work needed to be done to verify additions to the blockchain, that also implies people could be adding invalid content to the blockchain. Usually invalid stuff is easier to confirm than valid, but still, how easy is it to use invalid additions to spam the chain? Do valid transactions get validated on top of invalid transactions and require revalidation? Or is the initiator of the transaction responsible for recreating on a valid basis? I'm sure this is all basic blockchain stuff but it hadn't occurred to me before...

sleavey 5y ago
The "proof" part of proof of work used by Bitcoin is a small piece of information that proves that a lot of work has been done. An invalid proof can be easily checked by other nodes and ignored. In the case of Bitcoin the proof is a set of alphanumeric characters as input to the hashing algorithm (SHA256 I think) that produces a hash with certain properties (some number of leading zeros depending on the current difficulty). Other nodes can verify the proof by taking the input supplied by the miner, combining it with a predetermined nonce and computing the hash and checking that it has the properties required. Computing a single SHA256 is easy compared to figuring out which input to the hash produces a particular output. The next mined block will be appended to the longest valid blockchain the node can see. It's in their interest to append to the one that others will believe, because they get paid the reward only on that chain and thus it only exists in their wallet if others accept it by appending further blocks to it. So generating invalid blocks just doesn't work - they get immediately rejected by other nodes and there is thus no reward. One genuine problem is mining a valid block but adding no transactions to it, to grind transaction throughput to a halt. I think Bitcoin might have some mitigations for this but I don't actually know. If a sufficiently well funded organisation or nation tried to take down Bitcoin this might be the way to do it.
- alisonkisk 5y ago
  Empty blocks generate less revenue (no transaction fees, only the minig reward) but are slightly easier to create due to small mathematical flaws that let you skip some work if the block you create is empty. So for certain pools it's profitable in aggregate to mine empty blocks.

SubiculumCode 5y ago

There were some interesting tidbits in the article, but the claims of very low TPS in blockchain are a bit out of date, to be honest. Things are changing fast in ethereum, cardano, etc.

remram 5y ago
Isn't the usual fix to take transactions off the Blockchain? Similarly to how public key crypto is made faster by encrypting a symmetric key?
- jl2718 5y ago
  You can’t store a blockchain in a ZK-snark/stark either. You can only verify it. So the transactions take place ‘off the blockchain’ here as well. The difference is that they can be verified no matter where they occurred.
  - remram 5y ago
    What do you mean you can't store it?
    - jl2718 5y ago
      The ‘succinct’ part of the acronym means that the data is not stored in the proof.
lasc4r 5y ago
As has been the case for over 5 years.
SubiculumCode 5y ago
effing downvoters on blockchain topics. get an effing grip
- brink 5y ago
  If blockchain advocates didn't come of as so cult-ish, it'd be easier to not down-vote. But most advocates talk like blockchain exists in a vacuum. For example I saw a popular blockchain advocate talking about how the Pokemon company should get into NFT's and you have to wonder why? What advantage would it be to use blockchain over a simple database that the Pokemon company owns? I can think of several disadvantages. But the blockchain advocates keep harping on it whether it makes sense or not because it's financially advantageous for them.