8 ms·

I'm a bitcoin supporter (and user) for this among many other reasons.

by nannal 10y ago

AnimalMuppet 10y ago
I must admit that I don't understand the details of bitcoin. But if I understand correctly, can't a majority of owners block your transaction?
- jstanley 10y ago
  Most Bitcoin owners have absolutely no say in whether or not your transaction goes through. Only miners can do that. Big miners can easily delay your transaction, by refusing to include it in a block, but the only way they can prevent your transaction entirely is if all of the miners collude not to include it.
  - maxerickson 10y ago
    You only need collusion among a majority of mining power to ignore a transaction, not all miners. It's still effectively impossible because it would undermine confidence in the system (which is why people are willing to pay miners in the first place).
- schoen 10y ago
  It's very complicated to articulate exactly who can block Bitcoin transactions. The traditional simple answer is that "a majority of mining power" can block an individual transaction by refusing to include it in blocks. However, they have to be pretty committed to this, because if someone outside of the group does eventually mine a block that contains the censored transaction, the group members also have to be willing not to build on that block, and to trust each other not to do so. Just agreeing not to include the transaction in blocks themselves would be insufficient. At that point there are complicated questions about how stable and credible the arrangement will be, since systematically avoiding building on certain mined blocks involves slowing down the consensus slightly, and also trusting that the eventual consensus will exclude those blocks. If, say, 51% of mining power committed to censoring one particular transaction, that might yield an effective fork of Bitcoin for some period of time because the other 49% might gamble on their ability to get their rival blocks accepted in the long term (or, if they didn't know about the 51%'s policy, not see any reason why they shouldn't simply build on what appeared to be the longest chain!).
  - Retric 10y ago
    The economics of bitcoin and all alt coins mean some company will have the most efficient solution long term and thus mine far more than 51%. And once someone can mine 80+% of a block chain they can do what they want with it. PS: Add up the Chinese pools and one country effectively already controls bitcoin.
    - teod 10y ago
      For those out of the loop, miners work together in pools to combine their mining power. With more mining power, the more likely it is for them to mine a block (of the blockchain) and divide its payout among members of the pool. Pools cause centralization of mining power. You can see a list of pools and the percentage of their mining power at [https://blockchain.info/pools https://blockchain.info/pools]. Looking at the chart, you can see that the top 5 mining pools can collude in being a single entity to "control" the blockchain (I believe this is called a Sybil attack [https://en.wikipedia.org/wiki/Sybil_attack] https://en.wikipedia.org/wiki/Sybil_attack]). Now keeping incentives in mind, the idea is that people using bitcoin have faith in the system. That gives bitcoins value. Miners get paid in bitcoin. If they were to manipulate the blockchain, that would most likely cause bitcoin's userbase to lose faith in the system and thus what the miners would be stealing would suddenly have little to no value. I'm not positive, but I recall hearing that pools have been intentionally been made smaller to keep users' faith in the system. Perhaps the goal of these majority mining power is not to steal bitcoin but censor certain users? That may be a bit more complicated depending on the users' opinions on a case-by-case basis. Fun stuff :)
      - wyldfire 10y ago
        A Sybil attack is unrelated to consensus, but otherwise what you said is accurate. A Sybil attack can occur when a system designer mistakes a system identity to be exclusive with other ones. e.g. you could create a website that used a phone number as a user identifier and give every new user a $5 signup bonus. But if someone found a way to create valid phone numbers for less than $5 each, they could exploit your new user bonus system. If it's free/cheap/easy to create new identities, you must be careful how much weight to give those identities. e.g. reddit has some problems related to how easy it is to manipulate voting. They have probably made changes to their algorithm over the years to deweight new/unverified users and likely other clever things to detect voting rings.
Casseres 10y ago
I'm a Monero supporter (and owner and future user once more widely adopted) because like cash, no one can tell how much money you have in your wallet or who you're buying things from. With Bitcoin, neither of those is true.
- nullc 10y ago
  > With Bitcoin, neither of those is true. How much money is in my Bitcoin wallet?
  - pedrocr 10y ago
    Once you give out its address for someone to send you what they owe you they will know, which is not the case with your physical wallet or your bank account.
    - jstanley 10y ago
      They'll know how much is in that address, but a wallet consists of many addresses. How do you find all of the other addresses? If you watch for long enough, you can wait for a transaction that spends from the address you know, and you might find some other addresses that were spent with it. It's true that a non-zero amount of information about your Bitcoin holdings is leaked. But it's not true that that amount is 100%.
      - deleted 10y ago
        [deleted]
- deleted 10y ago
  [deleted]
JumpCrisscross 10y ago
I don't see how Bitcoin solves the anonymity problem cash does. If anything, banks and intelligence agencies would love a world where everyone transacts on a distributed ledger.
- modeless 10y ago
  It doesn't solve anonymity, but it does solve the permission problem. You can transfer unlimited amounts of Bitcoin at any time and place without anyone's permission or approval.
  - problems 10y ago
    But they can still come and beat you for it. Other cryptocurrencies like ZCash, Monero, etc solve this in a more elegant way by making transaction actually anonymous.
    - modeless 10y ago
      While Bitcoin is not completely anonymous, it is also not completely transparent. The blockchain does not contain names and things can be obfuscated in various ways. Furthermore, a truly 100% anonymous system of money without any exceptions may not actually be desirable from a societal point of view, as it would enable things like assassination markets.
      - modeless 10y ago
        I'll also add that if Bitcoin had started out completely anonymous like Zcash, it likely would have been outlawed in many countries by now including the US and China. Certainly no exchanges connected to the traditional banking system would be allowed to exist.
- thraway2016 10y ago
  Cash isn't really anonymous either. Serial numbers make it traceable, albeit with large time granularity. All banks and many large retailers track deposits and payments by serial number. That plus CCTV and cell tower data will usually be enough to identify someone with a pattern of spending dirty money.

I'm a bitcoin supporter (and user) for this among many other reasons.

by nannal 10y ago

I'm a bitcoin supporter (and user) for this among many other reasons.

I must admit that I don't understand the details of bitcoin. But if I understand correctly, can't a majority of owners block your transaction?

jstanley 10y ago
Most Bitcoin owners have absolutely no say in whether or not your transaction goes through. Only miners can do that. Big miners can easily delay your transaction, by refusing to include it in a block, but the only way they can prevent your transaction entirely is if all of the miners collude not to include it.
- maxerickson 10y ago
  You only need collusion among a majority of mining power to ignore a transaction, not all miners. It's still effectively impossible because it would undermine confidence in the system (which is why people are willing to pay miners in the first place).
schoen 10y ago
It's very complicated to articulate exactly who can block Bitcoin transactions. The traditional simple answer is that "a majority of mining power" can block an individual transaction by refusing to include it in blocks. However, they have to be pretty committed to this, because if someone outside of the group does eventually mine a block that contains the censored transaction, the group members also have to be willing not to build on that block, and to trust each other not to do so. Just agreeing not to include the transaction in blocks themselves would be insufficient. At that point there are complicated questions about how stable and credible the arrangement will be, since systematically avoiding building on certain mined blocks involves slowing down the consensus slightly, and also trusting that the eventual consensus will exclude those blocks. If, say, 51% of mining power committed to censoring one particular transaction, that might yield an effective fork of Bitcoin for some period of time because the other 49% might gamble on their ability to get their rival blocks accepted in the long term (or, if they didn't know about the 51%'s policy, not see any reason why they shouldn't simply build on what appeared to be the longest chain!).
- Retric 10y ago
  The economics of bitcoin and all alt coins mean some company will have the most efficient solution long term and thus mine far more than 51%. And once someone can mine 80+% of a block chain they can do what they want with it. PS: Add up the Chinese pools and one country effectively already controls bitcoin.
  - teod 10y ago
    For those out of the loop, miners work together in pools to combine their mining power. With more mining power, the more likely it is for them to mine a block (of the blockchain) and divide its payout among members of the pool. Pools cause centralization of mining power. You can see a list of pools and the percentage of their mining power at [https://blockchain.info/pools https://blockchain.info/pools]. Looking at the chart, you can see that the top 5 mining pools can collude in being a single entity to "control" the blockchain (I believe this is called a Sybil attack [https://en.wikipedia.org/wiki/Sybil_attack] https://en.wikipedia.org/wiki/Sybil_attack]). Now keeping incentives in mind, the idea is that people using bitcoin have faith in the system. That gives bitcoins value. Miners get paid in bitcoin. If they were to manipulate the blockchain, that would most likely cause bitcoin's userbase to lose faith in the system and thus what the miners would be stealing would suddenly have little to no value. I'm not positive, but I recall hearing that pools have been intentionally been made smaller to keep users' faith in the system. Perhaps the goal of these majority mining power is not to steal bitcoin but censor certain users? That may be a bit more complicated depending on the users' opinions on a case-by-case basis. Fun stuff :)
    - wyldfire 10y ago
      A Sybil attack is unrelated to consensus, but otherwise what you said is accurate. A Sybil attack can occur when a system designer mistakes a system identity to be exclusive with other ones. e.g. you could create a website that used a phone number as a user identifier and give every new user a $5 signup bonus. But if someone found a way to create valid phone numbers for less than $5 each, they could exploit your new user bonus system. If it's free/cheap/easy to create new identities, you must be careful how much weight to give those identities. e.g. reddit has some problems related to how easy it is to manipulate voting. They have probably made changes to their algorithm over the years to deweight new/unverified users and likely other clever things to detect voting rings.

Casseres 10y ago

I'm a Monero supporter (and owner and future user once more widely adopted) because like cash, no one can tell how much money you have in your wallet or who you're buying things from. With Bitcoin, neither of those is true.

nullc 10y ago
> With Bitcoin, neither of those is true. How much money is in my Bitcoin wallet?
- pedrocr 10y ago
  Once you give out its address for someone to send you what they owe you they will know, which is not the case with your physical wallet or your bank account.
  - jstanley 10y ago
    They'll know how much is in that address, but a wallet consists of many addresses. How do you find all of the other addresses? If you watch for long enough, you can wait for a transaction that spends from the address you know, and you might find some other addresses that were spent with it. It's true that a non-zero amount of information about your Bitcoin holdings is leaked. But it's not true that that amount is 100%.
    - deleted 10y ago
      [deleted]
deleted 10y ago
[deleted]

JumpCrisscross 10y ago

I don't see how Bitcoin solves the anonymity problem cash does. If anything, banks and intelligence agencies would love a world where everyone transacts on a distributed ledger.

modeless 10y ago
It doesn't solve anonymity, but it does solve the permission problem. You can transfer unlimited amounts of Bitcoin at any time and place without anyone's permission or approval.
- problems 10y ago
  But they can still come and beat you for it. Other cryptocurrencies like ZCash, Monero, etc solve this in a more elegant way by making transaction actually anonymous.
  - modeless 10y ago
    While Bitcoin is not completely anonymous, it is also not completely transparent. The blockchain does not contain names and things can be obfuscated in various ways. Furthermore, a truly 100% anonymous system of money without any exceptions may not actually be desirable from a societal point of view, as it would enable things like assassination markets.
    - modeless 10y ago
      I'll also add that if Bitcoin had started out completely anonymous like Zcash, it likely would have been outlawed in many countries by now including the US and China. Certainly no exchanges connected to the traditional banking system would be allowed to exist.
thraway2016 10y ago
Cash isn't really anonymous either. Serial numbers make it traceable, albeit with large time granularity. All banks and many large retailers track deposits and payments by serial number. That plus CCTV and cell tower data will usually be enough to identify someone with a pattern of spending dirty money.