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How does a blockchain solve the anonymity and routing problem? If I post anything on a public blockchain it will be cryptographically verified to have come from

by memexy 6y ago

How does a blockchain solve the anonymity and routing problem? If I post anything on a public blockchain it will be cryptographically verified to have come from a specific account because all transactions are signed: https://blog.signatura.co/using-the-blockchain-as-a-digital-signature-scheme-f584278ae826 https://blog.signatura.co/using-the-blockchain-as-a-digital-.... > Bitcoin uses digital signatures (ECDSA) to prove ownership of funds, so sending bitcoins requires the owner of them to digitally sign authorizing the transfer. This transaction is sent to Bitcoin’s public network and later recorded in Bitcoin’s public database (blockchain), so anyone can verify it by checking its digital signature. If everything is signed and verified to come from a specific account then that's by definition not anonymous. To be anonymous it would need to be the case that no one could figure out who sent the transaction (making the sender of the transaction anonymous), i.e. it couldn't be tied back to any specific account.

lend000 6y ago
Perhaps you are not familiar with Monero or Zcash.
- memexy 6y ago
  I'm not familiar with many things. How does Monero or Zcash solve the problem of anonymity.
  - zaarn 6y ago
    Monero uses ring-signatures; every transaction is signed by multiple signatures and it's impossible who is the actual signer. You also cannot tell what public address belongs to the signature, nor which public address is supposed to be the recipient. There is a reveal key that you can give tax authorities to reveal only you as a sender or receiver of a transaction but not the other end of it. Monero makes it impossible to tell what is what and gives people who want to trace money a very hard time doing so. ZCash uses Zero Knowledge Proofs. A ZK Proof (in this case zkSNARKs) is a way you can prove that you own a key to a second party without a third party being able to tell if there was an actual key involved (it is very easy for two colluding parties to fake a successfull ZK Proof). IIRC ZCash basically allows you to prove that a transaction has moved money correctly between two accounts without revealing what accounts those are or how much money was transacted. There is knowlegde of how much money is in the shielded pool, ie, all money behind ZK Proofs. Either approach has different advantages and disadvantages.
    - memexy 6y ago
      Makes sense. I remember going to a bay area talk about Bulletproofs but the talk was abstract enough that I didn't get too much out of it. Interesting to see that Monero is using them.

by memexy 6y ago

lend000 6y ago

Perhaps you are not familiar with Monero or Zcash.

memexy 6y ago
I'm not familiar with many things. How does Monero or Zcash solve the problem of anonymity.
- zaarn 6y ago
  Monero uses ring-signatures; every transaction is signed by multiple signatures and it's impossible who is the actual signer. You also cannot tell what public address belongs to the signature, nor which public address is supposed to be the recipient. There is a reveal key that you can give tax authorities to reveal only you as a sender or receiver of a transaction but not the other end of it. Monero makes it impossible to tell what is what and gives people who want to trace money a very hard time doing so. ZCash uses Zero Knowledge Proofs. A ZK Proof (in this case zkSNARKs) is a way you can prove that you own a key to a second party without a third party being able to tell if there was an actual key involved (it is very easy for two colluding parties to fake a successfull ZK Proof). IIRC ZCash basically allows you to prove that a transaction has moved money correctly between two accounts without revealing what accounts those are or how much money was transacted. There is knowlegde of how much money is in the shielded pool, ie, all money behind ZK Proofs. Either approach has different advantages and disadvantages.
  - memexy 6y ago
    Makes sense. I remember going to a bay area talk about Bulletproofs but the talk was abstract enough that I didn't get too much out of it. Interesting to see that Monero is using them.