3 ms·

> even if that information is encrypted. Assuming that information is only visible to the owner of the key anyways, then disposing of the key effectively rende

by judge2020 5y ago

> even if that information is encrypted. Assuming that information is only visible to the owner of the key anyways, then disposing of the key effectively renders that encrypted data as garbage. Not being able to delete it only enables some unknown future attack that can decrypt any data without the key.

vorpalhex 5y ago
For now. If the blockchain survives long enough, that info will become public in time.
- jimmaswell 5y ago
  We invade the privacy of people from a few hundred years ago all the time and it's considered fine. Do you think there will be a breakthrough in encryprion breaking soon enough for it to matter?
  - xg15 5y ago
    Assuming this will take a few hundred years. Browsers have to frequently deprecate cryptosystems that have become insecure. That's not possible with data frozen inside the blockchain. Also, we're at a point where quantom computers are just starting to become practically usable. So yes, I think the point of a "cryptographic breakthrough" that will crack some configurations is quite likely.
    - barsonme 5y ago
      If AES is broken in your lifetime, you're going to have _way_ bigger problems than somebody decrypting your blockchain ciphertext. And if you're not encrypting data with AES (or one of a handful of other algorithms), then you should be worried _now_.
      - xg15 5y ago
        If all of AES, then yes. But a particular choice of algorithm parameters can become insecure much earlier. > If AES is broken in your lifetime, you're going to have _way_ bigger problems than somebody decrypting your blockchain ciphertext. I'm not so sure about that. Not a lot of encrypted data is simply lying around at rest, available for everyone to run attacks against. Most encrypted data is either ephemeral (encrypted data connections) or secured by additional measures (e.g. to even get the raw bytes of an encrypted partition, you need access to the machine, appropriate permissions, etc) That gives the data owners various opportunities to react and mitigate the risks: Stop processes that send sensitive data, unmount sensitive partitions, detete data, etc. You can't do a lot to protect data on the blockchain - it's literally out there for everyone to access.
        onion2k 5y ago
        AES being broken doesn't mean someone managed to brute force a key. It means someone found a flaw that enables them to break any key in much less time than you'd expect a brute force attack to take. In other words, if AES is broken people would be able to read that ephemeral data quickly enough for it to be useful.
        xg15 5y ago
        I know - and the ephemeral data that attackers were able to capture would of course be at risk. My point was that data owners have options to limit damage - e.g. immediately stopping any data transmission and not producing any future ephemeral data.
        barsonme 5y ago
        That’s a very optimistic opinion :) And just to nitpick about blockchains, ledgers, etc.: they don’t need to be world-readable. You can protect them the same as you would a regular database.
        xg15 5y ago
        > You can protect them the same as you would a regular database. Then you'll need some central entity to manage access to the chain. If you already have a central entity, you can just use a regular database instead of a blockchain and save yourself all the energy waste.
rapind 5y ago
But it doesn’t though right? If there’s a database breach 10 years from now and I’m able to crack pki with like a quantum computer or something then I have that data… I think.
- jacobr1 5y ago
  You don't need the breach, the DB is already public (in encrypted form). So yeah, all you need is either a currently unknown mathematic weakness in the encryption scheme, or bug in implementation, or as you suggest some future quantum or other technical advance that defeats the encryption.
  - xxs 5y ago
    AES is =not= weak vs quantum computers.
xxs 5y ago
Likely the encryption key (per user) should be split between central and distributed (device) system. That way the operator can remove any identifiable user from the chain. Leaks of the central system won't have an immediate effect, either. Still quite a bizarre case.

vorpalhex 5y ago

For now. If the blockchain survives long enough, that info will become public in time.

jimmaswell 5y ago
We invade the privacy of people from a few hundred years ago all the time and it's considered fine. Do you think there will be a breakthrough in encryprion breaking soon enough for it to matter?
- xg15 5y ago
  Assuming this will take a few hundred years. Browsers have to frequently deprecate cryptosystems that have become insecure. That's not possible with data frozen inside the blockchain. Also, we're at a point where quantom computers are just starting to become practically usable. So yes, I think the point of a "cryptographic breakthrough" that will crack some configurations is quite likely.
  - barsonme 5y ago
    If AES is broken in your lifetime, you're going to have _way_ bigger problems than somebody decrypting your blockchain ciphertext. And if you're not encrypting data with AES (or one of a handful of other algorithms), then you should be worried _now_.
    - xg15 5y ago
      If all of AES, then yes. But a particular choice of algorithm parameters can become insecure much earlier. > If AES is broken in your lifetime, you're going to have _way_ bigger problems than somebody decrypting your blockchain ciphertext. I'm not so sure about that. Not a lot of encrypted data is simply lying around at rest, available for everyone to run attacks against. Most encrypted data is either ephemeral (encrypted data connections) or secured by additional measures (e.g. to even get the raw bytes of an encrypted partition, you need access to the machine, appropriate permissions, etc) That gives the data owners various opportunities to react and mitigate the risks: Stop processes that send sensitive data, unmount sensitive partitions, detete data, etc. You can't do a lot to protect data on the blockchain - it's literally out there for everyone to access.
      - onion2k 5y ago
        AES being broken doesn't mean someone managed to brute force a key. It means someone found a flaw that enables them to break any key in much less time than you'd expect a brute force attack to take. In other words, if AES is broken people would be able to read that ephemeral data quickly enough for it to be useful.
        xg15 5y ago
        I know - and the ephemeral data that attackers were able to capture would of course be at risk. My point was that data owners have options to limit damage - e.g. immediately stopping any data transmission and not producing any future ephemeral data.
      - barsonme 5y ago
        That’s a very optimistic opinion :) And just to nitpick about blockchains, ledgers, etc.: they don’t need to be world-readable. You can protect them the same as you would a regular database.
        xg15 5y ago
        > You can protect them the same as you would a regular database. Then you'll need some central entity to manage access to the chain. If you already have a central entity, you can just use a regular database instead of a blockchain and save yourself all the energy waste.

rapind 5y ago

But it doesn’t though right? If there’s a database breach 10 years from now and I’m able to crack pki with like a quantum computer or something then I have that data… I think.

jacobr1 5y ago
You don't need the breach, the DB is already public (in encrypted form). So yeah, all you need is either a currently unknown mathematic weakness in the encryption scheme, or bug in implementation, or as you suggest some future quantum or other technical advance that defeats the encryption.
- xxs 5y ago
  AES is =not= weak vs quantum computers.

xxs 5y ago

Likely the encryption key (per user) should be split between central and distributed (device) system. That way the operator can remove any identifiable user from the chain. Leaks of the central system won't have an immediate effect, either. Still quite a bizarre case.