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This is extraordinarily well done and begs to be shared widely. Agreed, this is a wonderful demonstration of the interesting principles behind the idea of a bl

This is extraordinarily well done and begs to be shared widely. Agreed, this is a wonderful demonstration of the interesting principles behind the idea of a blockchain (or a distributed merkle tree). Definitely worth playing with for anyone interested in this, and the video is a nice overview as well. As far as the moon being the limit, unfortunately we still inhabit the corrupted sublunary sphere, and blockchain technology (at least as implemented in Bitcoin) has some limitations which make it unsuitable as a currency or log of transactions between untrusted parties. On your last point, I'm not really sure people know what problems blockchain solves, because there are no problems which directly map to this solution, and there are plenty of problems it half-solves. Problems it purports to solve but fails at: Anonymity - good enough to protect criminals, not good enough to protect citizens against a state Trustless consensus - 51% attack makes this unreliable, esp. with semi-anonymous actors Trustless transactions - POW as in bitcoin makes this impractical due to energy use and delays People want centralised trust in many cases for verified identity, transaction rollback, legal constraints on transactions, so in an important sense it is solving the wrong problems (pseudo-anonymity, fungible cash, sort-of trustless consensus) while leaving important problems untouched. Still, the video and website are an excellent demonstration of the ideas behind a blockchain or Bitcoin.

colordrops 10y ago
I'm not sure what you mean in your explanation that it fails at trustless transactions. Also, you are ignoring the main driving force for the development of bitcoin, that being the removal of the middleman/governments from the transaction.
- grey-area 10y ago
  Bitcoin has failed to keep govs out of transactions between individuals because governments impose their will by force.
  - colordrops 10y ago
    If you are not trying to exchange currency, they can't really impose anything by force. You are taking about a failure of the exchange system, not bitcoin.
c0achmcguirk 10y ago
Anonymity - good enough to protect criminals, not good enough to protect citizens against a state If you really want anonymity, bitcoin isn't the only blockchain technology you have. I know you were focusing on bitcoin in your answer, but I feel the need to expand here because blockchain != bitcoin. Trustless consensus - 51% attack makes this unreliable, esp. with semi-anonymous actors 51% attack is overblown. The bitcoin miners self-police and are switching pools as they get close to 50%. And the worst thing that could happen with a 51% is a double-spend. Big whoop. Trustless transactions - POW as in bitcoin makes this impractical due to energy use and delays I don't follow you here. Sometimes the block size limit delays a transaction for a bit, but you still get trustless transactions. The bitcoin community is working to address this problem and I am confident this problem will be solved.
- grey-area 10y ago
  Anonymity - most people don't need or want it, and those who do need real anonymity, not traceable pseudo-anonymity. 51% attack - consider other uses like a shared ledger between 5 big banks, all of a sudden you just need 3 colluding and your blockchain is broken. Or bitcoin, most of the miners are in China, the state intervenes one day and secretly requires collusion. POW - 7 transactions a second, minutes to confirm and massive costs for those keeping full copies of the chain are big stumbling blocks to any blockchain based on POW as in the example or bitcoin. I think it has some fascinating ideas around shared trust, but Blockchains based on POW are fundamentally unsuited to the sort of large networks of transactions they are being proposed for and centralised solutions involving signing or hashing have the same advantages but solve all these problems and others like trust.
  - Natanael_L 10y ago
    Things like Lightning Network helps Bitcoin scale by creating a network of payment channels, where you work with "transaction drafts" shared between various nodes that are updated for every transaction made by the involved parties, and which is frequently "settled" on the blockchain by being published to it in its latest version (followed by creating a new "draft"). This means that only a fraction of all transactions actually need to be visible on the blockchain since LN is a secure way to "keep tabs" on the current coin ownership. Using multisignature mechanisms and timelocks, this is very secure and abuse resistant.
mthoms 10y ago
Those are indeed valid criticisms of Bitcoin. But Bitcoin != blockchain (and vice-versa). There are hundreds of different blockchain implementations. That includes some, for example that will rely on Proof of Stake as opposed to POW. Thus solving the trust and energy problems you mention. Well at least that's the theory :-) Time will tell.

colordrops 10y ago

I'm not sure what you mean in your explanation that it fails at trustless transactions. Also, you are ignoring the main driving force for the development of bitcoin, that being the removal of the middleman/governments from the transaction.

grey-area 10y ago
Bitcoin has failed to keep govs out of transactions between individuals because governments impose their will by force.
- colordrops 10y ago
  If you are not trying to exchange currency, they can't really impose anything by force. You are taking about a failure of the exchange system, not bitcoin.

c0achmcguirk 10y ago

Anonymity - good enough to protect criminals, not good enough to protect citizens against a state If you really want anonymity, bitcoin isn't the only blockchain technology you have. I know you were focusing on bitcoin in your answer, but I feel the need to expand here because blockchain != bitcoin. Trustless consensus - 51% attack makes this unreliable, esp. with semi-anonymous actors 51% attack is overblown. The bitcoin miners self-police and are switching pools as they get close to 50%. And the worst thing that could happen with a 51% is a double-spend. Big whoop. Trustless transactions - POW as in bitcoin makes this impractical due to energy use and delays I don't follow you here. Sometimes the block size limit delays a transaction for a bit, but you still get trustless transactions. The bitcoin community is working to address this problem and I am confident this problem will be solved.

grey-area 10y ago
Anonymity - most people don't need or want it, and those who do need real anonymity, not traceable pseudo-anonymity. 51% attack - consider other uses like a shared ledger between 5 big banks, all of a sudden you just need 3 colluding and your blockchain is broken. Or bitcoin, most of the miners are in China, the state intervenes one day and secretly requires collusion. POW - 7 transactions a second, minutes to confirm and massive costs for those keeping full copies of the chain are big stumbling blocks to any blockchain based on POW as in the example or bitcoin. I think it has some fascinating ideas around shared trust, but Blockchains based on POW are fundamentally unsuited to the sort of large networks of transactions they are being proposed for and centralised solutions involving signing or hashing have the same advantages but solve all these problems and others like trust.
- Natanael_L 10y ago
  Things like Lightning Network helps Bitcoin scale by creating a network of payment channels, where you work with "transaction drafts" shared between various nodes that are updated for every transaction made by the involved parties, and which is frequently "settled" on the blockchain by being published to it in its latest version (followed by creating a new "draft"). This means that only a fraction of all transactions actually need to be visible on the blockchain since LN is a secure way to "keep tabs" on the current coin ownership. Using multisignature mechanisms and timelocks, this is very secure and abuse resistant.

mthoms 10y ago

Those are indeed valid criticisms of Bitcoin. But Bitcoin != blockchain (and vice-versa). There are hundreds of different blockchain implementations. That includes some, for example that will rely on Proof of Stake as opposed to POW. Thus solving the trust and energy problems you mention. Well at least that's the theory :-) Time will tell.