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> and the blockchain, a type of decentralised ledger, could anonymise it How would "the blockchain" anonymise anything? Isn't it the opposite, if all transacti

• NDT 9y ago
  Anonymity comes from not knowing someone's bitcoin address which in many cases is safe to assume.
  • beagle3 9y ago
    It is never safe to assume, because it could be (retroactively) revealed at any point in the future. The right term for this is pseudonymity[0], not anonymity. [0] https://en.wikipedia.org/wiki/Pseudonymity https://en.wikipedia.org/wiki/Pseudonymity
    • devdoomari 9y ago
      but... how? suppose money went from A-->B-->C-->D-->E, and B,C,D never uses an bitcoin exchange / other 'offline' purchase / etc. (Also, B could send to C1, C2, C3 and then so on to hide the track.) then, how can anyone be sure that A,B,C,D are the same person/different person? Or... by "retroactively" - do you mean sometime in the future (hopefully far far away) where bitcoin's hash algo. is broken?
      • georgyo 9y ago
        Or the simpler answers, something on your computer reveals it, like malware. Or the person who sent/received money to/from you revels who you are, or information which helps identify who you are. Or there are warents authorizing authorities to take your devices and then they have all your identies. Also when you send Bitcoin from a wallet that has received money to multiple addresses, you can't be sure which coins are being sent. As such they can also associate multiple addresses together by which coins they sent.
      • qiqitori 9y ago
        By design, every single transaction is tracked. Otherwise you'd have a hard time proving that you have any BTC at all. In fact, the miners implicitly verify that all purchases are tracked, by doing something like the following every "block": new_hash = hash(previous_hash . all_new_transactions . random_number) You won't immediately know if A, B, C, and D are all the same person, but you can look at what has happened at those addresses (or previous addresses) in the past, and (eventually) what happens in the future, and draw conclusions from that. If you use a new address for every transaction, and never merge your money, you may be able to obfuscate the flow for a while, but you have to make sure you don't leave any patterns in the timestamps, and make sure you generally know what you're doing. Any mistake could mean that people know it's you. Moreover, money is generally used for 'offline' things eventually. You may purchase something from a completely normal person who doesn't obfuscate his transfers at all, and then get outed when the police ask that guy who they got those suspicious coins from.
• DennisP 9y ago
  ZCash and Monero have strong cryptographic privacy (ZCash with zksnarks, Monero with ring signatures). Neither has smart contracts, which you'd want for this application, but the privacy technologies from both will be available in Ethereum after the upcoming Metropolis release.
  • runeks 9y ago
    And both technologies are at the research stage, it should be noted (both ZCash and Monero have suffered from vulnerabilities that allowed attackers to create tokens out of nowhere).
    • capnrefsmmat 9y ago
      The attack you're thinking of was on Zerocoin, not ZCash; Zerocoin wasn't built by the team that came up with the zero-knowledge proof ideas, and was built on top of the original Bitcoin client code IIRC. https://news.ycombinator.com/item?id=13672117 https://news.ycombinator.com/item?id=13672117
      • runeks 9y ago
        I stand corrected. However, in the thread you link you it's pointed out that ZCash has no auditing built in, so it's not possible to actually see how many coins are in circulation. So saying ZCash hasn't suffered from a bug of this nature would be presumptuous, although it may be perfectly correct.
• utnick 9y ago
  Also how would it work if everyone is anonymous? Don't you need to know when people die?