Sorry, you must have meant all 12 bytes. That makes finding a collision substantially harder. However, you may have to restrict yourself to 10 bytes because you don't know if any hardware does timestamp rolling on-chip. Also you create an incentive to mess around with the version bits instead, so you would have to fix that as well. So it basically means a new mining header with the real blockheader as a child header. On Wed, May 11, 2016 at 9:24 AM, Timo Hanke wrote: > Luke, do you mean to replace the first 4 bytes of the second chunk (bytes > 64..67 in 0-based counting) by the XOR of those 4 bytes with the first 4 > bytes of the midstate? (I assume you don't care about 12 bytes but rather > those 4 bytes.) > > This does not work. All it does is adding another computational step > before you can check for a collision in those 4 bytes. It makes finding a > collision only marginally harder. > > On Wed, May 11, 2016 at 7:28 AM, Luke Dashjr via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > >> On Wednesday, May 11, 2016 12:20:55 PM Sergio Demian Lerner via >> bitcoin-dev >> wrote: >> > On Tue, May 10, 2016 at 6:43 PM, Sergio Demian Lerner < >> > sergio.d.lerner@gmail.com> wrote: >> > > You can find it here: >> > > >> https://bitslog.wordpress.com/2014/03/18/the-re-design-of-the-bitcoin-blo >> > > ck-header/ >> > > >> > > Basically, the idea is to put in the first 64 bytes a 4 byte hash of >> the >> > > second 64-byte chunk. That design also allows increased nonce space in >> > > the first 64 bytes. >> > >> > My mistake here. I didn't recalled correctly my own idea. The idea is to >> > include in the second 64-byte chunk a 4-byte hash of the first chunk, >> not >> > the opposite. >> >> What if we XOR bytes 64..76 with the first 12 bytes of the SHA2 midstate? >> Would that work? >> >> Luke >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> > >