On 10/15/19 8:50 AM, Joachim Strömbergson wrote: >>>>> [...] to generate much longer chain with superslow timestamp increase (~5 >>>>> blocks in 1 second) without increasing difficulty (i.e. staying at min. >>>>> diff.). [...] >>>>> In that case, it would take about 7 minutes of block time seconds for >>>>> the next retarget period, every 2016 blocks, and the difficulty would >>>>> adjust. The difficulty would adjust in that case as if 2 weeks of blocks >>>>> had been mined in 7 minutes. For the difficulty to remain the same the >>>>> time between blocks needs to be 10 minutes. >>>>> This calculation does not apply under time warp attack. You can fake >>>>> timestamps of all blocks except for those relevant to the retarget >>>>> calculation. Those are only the first and the last block in the 2016 >>>>> block window. >> This must be in reference to the non-overlapping difficulty calculation >> and off-by-one bug? > Indeed. > Yeah, limiting the width of the chain would not be effective unless the timewarp off-by-one bug is resolved — the height can be extended instead.
Rate limiting based on chainwork would slow down a timewarped low work header chain. There would be a maximum rate at which the headers could be sent. It would be around 32KB/s. It would take about a month to send 100GB. _______________________________________________ bitcoin-dev mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
