Yesterday I had the opportunity to witness a "time warp" attack in progress on another Altcoin - Myriad.
Its terrifying to watch in real time - blocks generating faster than they can be displayed on your screen.
The attacker was able to reset difficultly to under 1 and produce a new block every second. In a short space of time they mined over 5,000 blocks - and the coins/blocks are all valid. Luckily the MYR devs had the fixes already on hand and the situation was fixed with 2 successive hard forks. MYR mines on 5 algo's simultaneously so this attack tested a very challenging target.
Quite a few coins have suffered this attack so far (Terracoin was a good first example.
https://www.youtube.com/watch?v=t8ffDIw0J3Q ) and it seems that many if not most are still vulnerable - apart from allowing someone to get away with a bunch of free coins it has the potential to fork the coin's blockchain and cause serious chaos that is difficult and time consuming to fix - right through to the exchanges. At some point when the coins are sold some poor entity ends up paying out on a double spend.
So just a question - how is UTC positioned for a time warp attack? With its current popularity/raised profile, short block time, quick difficulty re-targeting, relatively low hash and a relatively attractive price compared to MYR I could easily see UTC as a potential target in the near future. Seems the MYR attack was just a practice run as the returns would not be great for the attacker - but it worked and all coins generated were valid and spendable - and this was just yesterday.
Could UTC be on the target list? Does Scrypt Jane provide some inherent protection?
I would appreciate some comments from the devs on how robust UTC is for this issue.
If UTC is not robust on this I urge the devs to address this as a matter of priority.
