On Sun, Jun 21, 2015 at 11:31 AM, Jorge Timón <jtimon@jtimon.cc> wrote:

You mean the timewarp fix can be coded as a softfork instead of a
hardfork? How so?

The easiest would be a rule requiring that all blocks are within 1 day of the median of the previous 11 blocks. At the moment, you need to be greater than that value. This would add a condition at the other end.

It wouldn't be a total fix, but it would protect against the exploit.

A stricter soft fork would be that the two blocks in question have to have the same timestamp. This would force the off by 1 and the correct value to give the same result.

If that's the case, do you have a better candidate?

I think it is fine, since fixing it "right" does require a hard fork, especially if it is only to show a non controversial hard fork.