4 ms·

> Allowed buyers to take back payments they’d made after walking out of shops, by simply pressing a button (if you aren’t aware of this “feature” that’s because

by Siecje 11y ago

> Allowed buyers to take back payments they’d made after walking out of shops, by simply pressing a button (if you aren’t aware of this “feature” that’s because Bitcoin was only just changed to allow it What "feature" was recently added? This has always been a problem with BTC.

prutschman 11y ago
I think it's a reference to "Replace By Fee." I don't follow bitcoin closely enough to know exactly what this is, but here's an argument against: https://medium.com/@octskyward/replace-by-fee-43edd9a1dd6d#.zf4deyyiu https://medium.com/@octskyward/replace-by-fee-43edd9a1dd6d#....
- Siecje 11y ago
  That was a good explanation thank you.
  - kanzure 11y ago
    Here's some other details: https://www.reddit.com/r/Bitcoin/comments/3urm8o/optin_rbf_is_misunderstood_ask_questions_about_it/ https://www.reddit.com/r/Bitcoin/comments/3urm8o/optin_rbf_i...
patio11 11y ago
Replace by fee. Zero-confirmation transactions have always been insecure; replace-by-fee is essentially Firesheep for this vulnerability -- it puts a friendly UI on it and drops the technical acumen required from "substantial -- you probably have to write your own complicated C++ code" to "you have to be willing to lie; that's it." (Replace by fee in a nutshell: All Bitcoin transactions are unstable for a period of time, generally believed to be "approximately 60 minutes." Exploiting this instability to retroactively invalidate a transaction was possible but beyond the ken of casual attackers. Replace by fee lets you reverse any transaction you made younger than N minutes by simply saying "I'm willing to outbid the fee I offered on that transaction. The new transaction does this new thing, for example replacing the $100 transaction 'pay from my left pocket to restaurant for dinner' into 'pay from my left pocket to my right pocket.'")
- Siecje 11y ago
  Wasn't this always the case? The higher miner tip would get picked up.
  - hawkice 11y ago
    Not really, it used to be that they would just pick the first non-conflicting transaction they saw, although iirc that wasn't a "rule of the protocol" so much as how-the-software-worked.
  - rmc 11y ago
    There is a difference between "possible but hard" and "possible but easy".
mrb 11y ago
Mike is incorrect about this one. He is under the impression that replace by fee "RBF" was committed in Bitcoin Core and will ship with 0.12. In fact it is "opt-in RBF" that was committed: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-November/011783.html https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015... "Opt-in RBF" is generally viewed as a good thing unlike "RBF". Even Jeff Garzik who is against RBF approved opt-in RBF: https://twitter.com/jgarzik/status/671271910634889216 https://twitter.com/jgarzik/status/671271910634889216 I mentioned this in a comment at medium.com.

by Siecje 11y ago

prutschman 11y ago

I think it's a reference to "Replace By Fee." I don't follow bitcoin closely enough to know exactly what this is, but here's an argument against: https://medium.com/@octskyward/replace-by-fee-43edd9a1dd6d#.zf4deyyiu https://medium.com/@octskyward/replace-by-fee-43edd9a1dd6d#....

Siecje 11y ago
That was a good explanation thank you.
- kanzure 11y ago
  Here's some other details: https://www.reddit.com/r/Bitcoin/comments/3urm8o/optin_rbf_is_misunderstood_ask_questions_about_it/ https://www.reddit.com/r/Bitcoin/comments/3urm8o/optin_rbf_i...

patio11 11y ago

Replace by fee. Zero-confirmation transactions have always been insecure; replace-by-fee is essentially Firesheep for this vulnerability -- it puts a friendly UI on it and drops the technical acumen required from "substantial -- you probably have to write your own complicated C++ code" to "you have to be willing to lie; that's it." (Replace by fee in a nutshell: All Bitcoin transactions are unstable for a period of time, generally believed to be "approximately 60 minutes." Exploiting this instability to retroactively invalidate a transaction was possible but beyond the ken of casual attackers. Replace by fee lets you reverse any transaction you made younger than N minutes by simply saying "I'm willing to outbid the fee I offered on that transaction. The new transaction does this new thing, for example replacing the $100 transaction 'pay from my left pocket to restaurant for dinner' into 'pay from my left pocket to my right pocket.'")

Siecje 11y ago
Wasn't this always the case? The higher miner tip would get picked up.
- hawkice 11y ago
  Not really, it used to be that they would just pick the first non-conflicting transaction they saw, although iirc that wasn't a "rule of the protocol" so much as how-the-software-worked.
- rmc 11y ago
  There is a difference between "possible but hard" and "possible but easy".

mrb 11y ago

Mike is incorrect about this one. He is under the impression that replace by fee "RBF" was committed in Bitcoin Core and will ship with 0.12. In fact it is "opt-in RBF" that was committed: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-November/011783.html https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015... "Opt-in RBF" is generally viewed as a good thing unlike "RBF". Even Jeff Garzik who is against RBF approved opt-in RBF: https://twitter.com/jgarzik/status/671271910634889216 https://twitter.com/jgarzik/status/671271910634889216 I mentioned this in a comment at medium.com.