[Bitcoin-development] Time
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I thought I should shortcut my research by asking a direct question here. As I understand it, the blockchain actually provides an extra piece of reliable data that is not being exploited by applications. Which data? The time. In this case 'the time' as agreed by 50% of the participants, where those participants have a strong financial incentive to keep that 'time' fairly accurate. (+/- about 10 minutes) Is this a reasonable understanding of 'time'? ... aka timestamps on the block Ok... 'time' on the blockchain could be 'gamed' ... but with great difficulty. An application presented with a fake blockchain can use quite a few heuristics to test the 'validity' of the block chain. It can review the usual cryptographic proofs, and check that difficulty is growing/declining only in a realistic manner up to the most recent block. Even use some arbitrary test like difficulty 10,000,000,000 ... on the presumption that any less means that the Bitcoin system has failed massively from where it currently is and has become an unreliable time source. Reliable 'time' has been impossible up until now - because you need to trust the time source, and that can always be faked. Using the blockchain as an approximate time source gives you a world wide consensus without direct trust of any player. So if this presumption is correct, then we can now build time capsule applications that can not be tricked into exposing their contents too early by running them in a virtual environment with the wrong system time. Is this right? or did miss I something fundamental? Ron - -- public identify: https://www.onename.io/ron_ohara -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.20 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJT0a9sAAoJEAla1VT1+xc2ONQH/0R09guSNNCxP36KziAjfcBc JEhxMpIlqTTYEvNXaBmuPy4BN+IZQ9izgrW/cvlEJJNMmc5/VIBk83WZltmDwcKl oo4MIdmp6vz984GWToyyLcLSEDT60UE9Hhe+U9RyF5J9kwbN8Uy4ozUHhFVP/0EL q4O1V6ggPbHWgH4q8m8E9qWOlIFXCDgCjxpL8Ptxsk+UlBq2NWMiwTz6Tbc9KOB4 hOffzXCZV+DkwjFZD2Rc4rHaxw1yLuYr7DzmzwZbhRQclv9tZt9hoVaAT+RQpE1k X7pi+zVzeMMng0bzUv8t/G+gq0gaelyV41MJQRparEXhnuYkgU7rAPKIQEG8qpc= =T5fw -END PGP SIGNATURE- -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Time
The upcoming release of breadwallet uses the height of the blockchain to enforce timed pin code lockouts for preventing an attacker from quickly making multiple pin guesses. This prevents them changing the devices system time to get around the lockout period. Aaron On Thursday, July 24, 2014, Ron OHara ron.ohar...@gmail.com wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I thought I should shortcut my research by asking a direct question here. As I understand it, the blockchain actually provides an extra piece of reliable data that is not being exploited by applications. Which data? The time. In this case 'the time' as agreed by 50% of the participants, where those participants have a strong financial incentive to keep that 'time' fairly accurate. (+/- about 10 minutes) Is this a reasonable understanding of 'time'? ... aka timestamps on the block Ok... 'time' on the blockchain could be 'gamed' ... but with great difficulty. An application presented with a fake blockchain can use quite a few heuristics to test the 'validity' of the block chain. It can review the usual cryptographic proofs, and check that difficulty is growing/declining only in a realistic manner up to the most recent block. Even use some arbitrary test like difficulty 10,000,000,000 ... on the presumption that any less means that the Bitcoin system has failed massively from where it currently is and has become an unreliable time source. Reliable 'time' has been impossible up until now - because you need to trust the time source, and that can always be faked. Using the blockchain as an approximate time source gives you a world wide consensus without direct trust of any player. So if this presumption is correct, then we can now build time capsule applications that can not be tricked into exposing their contents too early by running them in a virtual environment with the wrong system time. Is this right? or did miss I something fundamental? Ron - -- public identify: https://www.onename.io/ron_ohara -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.20 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJT0a9sAAoJEAla1VT1+xc2ONQH/0R09guSNNCxP36KziAjfcBc JEhxMpIlqTTYEvNXaBmuPy4BN+IZQ9izgrW/cvlEJJNMmc5/VIBk83WZltmDwcKl oo4MIdmp6vz984GWToyyLcLSEDT60UE9Hhe+U9RyF5J9kwbN8Uy4ozUHhFVP/0EL q4O1V6ggPbHWgH4q8m8E9qWOlIFXCDgCjxpL8Ptxsk+UlBq2NWMiwTz6Tbc9KOB4 hOffzXCZV+DkwjFZD2Rc4rHaxw1yLuYr7DzmzwZbhRQclv9tZt9hoVaAT+RQpE1k X7pi+zVzeMMng0bzUv8t/G+gq0gaelyV41MJQRparEXhnuYkgU7rAPKIQEG8qpc= =T5fw -END PGP SIGNATURE- -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net javascript:; https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Aaron Voisine breadwallet.com -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Time
Miners are free to set the block's timestamp to whatever they please, within a certain +/- time window. Time might even go backwards a tiny bit from the last block to the next block. On Thu, Jul 24, 2014 at 9:14 PM, Ron OHara ron.ohar...@gmail.com wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I thought I should shortcut my research by asking a direct question here. As I understand it, the blockchain actually provides an extra piece of reliable data that is not being exploited by applications. Which data? The time. In this case 'the time' as agreed by 50% of the participants, where those participants have a strong financial incentive to keep that 'time' fairly accurate. (+/- about 10 minutes) Is this a reasonable understanding of 'time'? ... aka timestamps on the block Ok... 'time' on the blockchain could be 'gamed' ... but with great difficulty. An application presented with a fake blockchain can use quite a few heuristics to test the 'validity' of the block chain. It can review the usual cryptographic proofs, and check that difficulty is growing/declining only in a realistic manner up to the most recent block. Even use some arbitrary test like difficulty 10,000,000,000 ... on the presumption that any less means that the Bitcoin system has failed massively from where it currently is and has become an unreliable time source. Reliable 'time' has been impossible up until now - because you need to trust the time source, and that can always be faked. Using the blockchain as an approximate time source gives you a world wide consensus without direct trust of any player. So if this presumption is correct, then we can now build time capsule applications that can not be tricked into exposing their contents too early by running them in a virtual environment with the wrong system time. Is this right? or did miss I something fundamental? Ron - -- public identify: https://www.onename.io/ron_ohara -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.20 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJT0a9sAAoJEAla1VT1+xc2ONQH/0R09guSNNCxP36KziAjfcBc JEhxMpIlqTTYEvNXaBmuPy4BN+IZQ9izgrW/cvlEJJNMmc5/VIBk83WZltmDwcKl oo4MIdmp6vz984GWToyyLcLSEDT60UE9Hhe+U9RyF5J9kwbN8Uy4ozUHhFVP/0EL q4O1V6ggPbHWgH4q8m8E9qWOlIFXCDgCjxpL8Ptxsk+UlBq2NWMiwTz6Tbc9KOB4 hOffzXCZV+DkwjFZD2Rc4rHaxw1yLuYr7DzmzwZbhRQclv9tZt9hoVaAT+RQpE1k X7pi+zVzeMMng0bzUv8t/G+gq0gaelyV41MJQRparEXhnuYkgU7rAPKIQEG8qpc= =T5fw -END PGP SIGNATURE- -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Jeff Garzik Bitcoin core developer and open source evangelist BitPay, Inc. https://bitpay.com/ -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Time
On Thu, Jul 24, 2014 at 7:35 PM, Aaron Voisine vois...@gmail.com wrote: The upcoming release of breadwallet uses the height of the blockchain to enforce timed pin code lockouts for preventing an attacker from quickly making multiple pin guesses. This prevents them changing the devices system time to get around the lockout period. Is breadwallet tamper resistant zero on tamper hardware? otherwise this sounds like security theater I attach a debugger to the process (or modify the program) and ignore the block sourced time. -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Time
On Thu, Jul 24, 2014 at 10:39 PM, Gregory Maxwell gmaxw...@gmail.com wrote: Is breadwallet tamper resistant zero on tamper hardware? otherwise this sounds like security theater I attach a debugger to the process (or modify the program) and ignore the block sourced time. It's an iOS application. I would imagine it is substantially more difficult to attach to a process (which, at the very least, requires root, and perhaps other things on iOS) than to convince the device to change its system time. That said, the security benefits might not be too substantial. -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Time
It's based on the block height, not the block's timestamp. If you have access to the device and the phone itself is not pin locked, then you can jailbreak it and get access to the wallet seed that way. A pin locked device however is reasonably secure as the filesystem is hardware aes encrypted to a combination of pin+uuid. This was just an easy way to prevent multiple pin guesses by changing system time in settings, so that isn't the weakest part of the security model. Aaron Voisine breadwallet.com On Thu, Jul 24, 2014 at 8:21 PM, William Yager will.ya...@gmail.com wrote: On Thu, Jul 24, 2014 at 10:39 PM, Gregory Maxwell gmaxw...@gmail.com wrote: Is breadwallet tamper resistant zero on tamper hardware? otherwise this sounds like security theater I attach a debugger to the process (or modify the program) and ignore the block sourced time. It's an iOS application. I would imagine it is substantially more difficult to attach to a process (which, at the very least, requires root, and perhaps other things on iOS) than to convince the device to change its system time. That said, the security benefits might not be too substantial. -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
