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Two questions I've yet to receive answers on: - my laptop is stolen in a compromised state (eg logged on, nothing left encrypted); can anyone trace my transact

Two questions I've yet to receive answers on: - my laptop is stolen in a compromised state (eg logged on, nothing left encrypted); can anyone trace my transactions? - I've read suggestions that Zcash themselves can deanonymize every transaction, thanks to generating the initial "Genesis" block. Is that roughly right? (Ignoring obfuscation techniques like getting many other people to create separate signatures) I'm definitely concerned that this comes with a lot of asterisks next to its claims.

vessenes 11y ago
1) Laptop stolen, unlocked, you never encrypted anything: yep, you're hosed as far as I know. How else would your wallet be able to tell you a balance? 2) The creation of the genesis block involves a trust 'game' of sorts, in which many participants are asked to pick a number. The statement from zcash, which a better cryptographer than me could verify, is that only one of the participants need be trustworthy in order to make this step safe. I think anyone can participate in the genesis block creation, so you may be just who they need to get the genesis block in good shape. :) On a different note, it would take a juvenile and short-sighted thinker to want to be able to deanonymize the transactions; not that those people don't exist, but most rational adults would not wish to be emotionally and personally liable in some way for knowing the identities of the money launderers, child pornographers and others who will undoubtedly be drawn to a technology like this.
- deleted 11y ago
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  - ultramancool 11y ago
    > I guess I just don't see enhanced ability to enforce laws a compelling enough reason to deny everyone privacy. I think he's saying the exact opposite - that it'd be short-sighted to _want_ to deanonymize people and to have to deal with those identities.
- Forbo 11y ago
  Ah, two of the Four Horsemen of the Infocalypse rear their ugly heads: 8.3.4. "How will privacy and anonymity be attacked?" [...] like so many other "computer hacker" items, as a tool for the "Four Horsemen": drug-dealers, money-launderers, terrorists, and pedophiles. https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalypse https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalyp...
  - omginternets 11y ago
    I think this moral panic (for lack of a better term) is omnipresent because it's actually true to some degree. You can't seriously claim these groups wouldn't benefit from anonymous, secure payment systems. However: - They already have anonymous, secure payment systems (cash, drugs, jewels, shell companies, etc) - The cat is out of the bag, so they're going to have it anyway - These proverbial Horsement do more than just move money around; there's still plenty of room for detective work. Splitting the atom gave us nuclear power, viable cancer treatment, smoke detectors, and also Hiroshima, Nagasaki, and the threat of radiological terrorism. The proverbial sword is always double-edged. To make an actual point: I think we'd do well as a community to acknowledge the degree of truth these moral panics hold, because I suspect we frustrate a lot of people by being dismissive of what they perceive to be an apocalyptic problem.
    - skybrian 11y ago
      I agree that we shouldn't be dismissive. However, I still think you are being somewhat dismissive when you say "The cat is out of the bag, so they're going to have it anyway." This is binary thinking but crime isn't binary. There are varying levels of crime. New technologies can make criminal behavior easier or more difficult. Just giving up on money laundering isn't something most people are willing to think about, particular for an experimental payment system that they don't care about and probably won't use. For someone who doesn't understand the benefits of a new technology and is rounding it to zero, the cost/benefit tradeoff isn't hard to decide, and making an analogy to splitting the atom is unlikely to be persuasive.
      - 11y ago
ianmiers 11y ago
Hi, I'm Ian, one of the scientists behind ZCash, Zerocash, and Zerocoin. -laptop being stolen: An attacker will get how much money you have, and if you have kept around the private keys for all your addresses, when and how much you were paid, but not who paid you or who you paid. The attacker can use those keys to go back and decrypt the notifications that get posted to the blockchain that allow you to access a transaction. This gets them how much funds you have been sent and when. It doesn't tell them who sent it unless someone put identifying info in the memo field(e.g.'For Homer Simpson's bar tab'), because senders are anonymous even to recipients. It also doesn't tell them anything directly about who you paid or how much. It does let them identify when you made payments though. If you move your funds to a new address and delete those keys, then all an attacker gets is your current balance. - deanonymize every transaction. We can't. The zero-knowledge proofs(zkSNARKS) we use to hide transaction data are zero-knowledge no matter what. The information simply isn't there. The confusion is there is an issue with setting things up to ensure we can't forge coins. The zkSNARKs that ZCash uses need to be generated correctly to ensure the proofs are sound (i.e. actually prove what they claim) and someone therefore cannot forge coins. We plan on doing a multiparty computation setup where if at least one party is honest, the parameters are correct. But zkSNARKs provide statistical zero-knowledge without trusted setup. So assuming the software correctly does the protocol, no one can ever deanonymize transactions (see my other comment on post quantum security for the caveats) unless they get your keys.
- mootothemax 11y ago
  Thanks Ian, I really appreciate your comprehensive answer :) - laptop being stolen: cutting out potential ifs and buts, would it be drastically unfair of me to take that as: if you laptop's compromised, all bets are off? - deanonymize every transaction: genuinely interesting, thanks for taking the time to educate me :)
  - ianmiers 11y ago
    Laptop being stolen: Certainly for normal users, yes. Don't let that happen. But you can protect yourself by moving funds to new addresses and deleting the old address keys. Poor man's forward secrecy. Since no one will probably do that, yeah .... all bets are off.

vessenes 11y ago

1) Laptop stolen, unlocked, you never encrypted anything: yep, you're hosed as far as I know. How else would your wallet be able to tell you a balance? 2) The creation of the genesis block involves a trust 'game' of sorts, in which many participants are asked to pick a number. The statement from zcash, which a better cryptographer than me could verify, is that only one of the participants need be trustworthy in order to make this step safe. I think anyone can participate in the genesis block creation, so you may be just who they need to get the genesis block in good shape. :) On a different note, it would take a juvenile and short-sighted thinker to want to be able to deanonymize the transactions; not that those people don't exist, but most rational adults would not wish to be emotionally and personally liable in some way for knowing the identities of the money launderers, child pornographers and others who will undoubtedly be drawn to a technology like this.

deleted 11y ago
[deleted]
- ultramancool 11y ago
  > I guess I just don't see enhanced ability to enforce laws a compelling enough reason to deny everyone privacy. I think he's saying the exact opposite - that it'd be short-sighted to _want_ to deanonymize people and to have to deal with those identities.
Forbo 11y ago
Ah, two of the Four Horsemen of the Infocalypse rear their ugly heads: 8.3.4. "How will privacy and anonymity be attacked?" [...] like so many other "computer hacker" items, as a tool for the "Four Horsemen": drug-dealers, money-launderers, terrorists, and pedophiles. https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalypse https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalyp...
- omginternets 11y ago
  I think this moral panic (for lack of a better term) is omnipresent because it's actually true to some degree. You can't seriously claim these groups wouldn't benefit from anonymous, secure payment systems. However: - They already have anonymous, secure payment systems (cash, drugs, jewels, shell companies, etc) - The cat is out of the bag, so they're going to have it anyway - These proverbial Horsement do more than just move money around; there's still plenty of room for detective work. Splitting the atom gave us nuclear power, viable cancer treatment, smoke detectors, and also Hiroshima, Nagasaki, and the threat of radiological terrorism. The proverbial sword is always double-edged. To make an actual point: I think we'd do well as a community to acknowledge the degree of truth these moral panics hold, because I suspect we frustrate a lot of people by being dismissive of what they perceive to be an apocalyptic problem.
  - skybrian 11y ago
    I agree that we shouldn't be dismissive. However, I still think you are being somewhat dismissive when you say "The cat is out of the bag, so they're going to have it anyway." This is binary thinking but crime isn't binary. There are varying levels of crime. New technologies can make criminal behavior easier or more difficult. Just giving up on money laundering isn't something most people are willing to think about, particular for an experimental payment system that they don't care about and probably won't use. For someone who doesn't understand the benefits of a new technology and is rounding it to zero, the cost/benefit tradeoff isn't hard to decide, and making an analogy to splitting the atom is unlikely to be persuasive.
    - 11y ago

ianmiers 11y ago

Hi, I'm Ian, one of the scientists behind ZCash, Zerocash, and Zerocoin. -laptop being stolen: An attacker will get how much money you have, and if you have kept around the private keys for all your addresses, when and how much you were paid, but not who paid you or who you paid. The attacker can use those keys to go back and decrypt the notifications that get posted to the blockchain that allow you to access a transaction. This gets them how much funds you have been sent and when. It doesn't tell them who sent it unless someone put identifying info in the memo field(e.g.'For Homer Simpson's bar tab'), because senders are anonymous even to recipients. It also doesn't tell them anything directly about who you paid or how much. It does let them identify when you made payments though. If you move your funds to a new address and delete those keys, then all an attacker gets is your current balance. - deanonymize every transaction. We can't. The zero-knowledge proofs(zkSNARKS) we use to hide transaction data are zero-knowledge no matter what. The information simply isn't there. The confusion is there is an issue with setting things up to ensure we can't forge coins. The zkSNARKs that ZCash uses need to be generated correctly to ensure the proofs are sound (i.e. actually prove what they claim) and someone therefore cannot forge coins. We plan on doing a multiparty computation setup where if at least one party is honest, the parameters are correct. But zkSNARKs provide statistical zero-knowledge without trusted setup. So assuming the software correctly does the protocol, no one can ever deanonymize transactions (see my other comment on post quantum security for the caveats) unless they get your keys.

mootothemax 11y ago
Thanks Ian, I really appreciate your comprehensive answer :) - laptop being stolen: cutting out potential ifs and buts, would it be drastically unfair of me to take that as: if you laptop's compromised, all bets are off? - deanonymize every transaction: genuinely interesting, thanks for taking the time to educate me :)
- ianmiers 11y ago
  Laptop being stolen: Certainly for normal users, yes. Don't let that happen. But you can protect yourself by moving funds to new addresses and deleting the old address keys. Poor man's forward secrecy. Since no one will probably do that, yeah .... all bets are off.