Never thought I would actually be able to see it happen, a blockchain split. Last friday the third of march 2017 it almost did. At least it looked like that was the case for Slothcoin. My local wallet got stuck at zero hours behind. Looked at the blockheight and still did not get it. Opened the build in console and there it was, an IP using version 1.2.1 had the highest blockcount. And it looked like mine was on the wrong chain.
At first I thought that our beloved Sloth was stuck in high difficulty again. That is when I fire up my GPU miner as long as it takes, to get it going again. This can happen when a big miner hits it with hundreds of Mega Hashes power per second and then leaves after a while. Pulling it out off a high diff is quite easy, yet not done in a jiffy. Sometimes it takes several hours. So far it worked every time. And when it has been done I sometimes keep mining a bit with one CPU core, using the build in Wallet miner of Slothcoin.
Unfortunately this was not the case. The blocks that were found by the GPU miner got a question mark and the Wallet stayed at zero blocks behind. Meaning it got stuck real bad and this was not due to a high difficulty level. At such a moment the debug.log file is helpfull as is the build in Wallet console. There it was an IP using a prehistoric version, 1.2.1, of Slothcoin. And that would not have been such a big deal, had it not managed to create a longer blockchain. Now, why, after such a long time, would one fire up an outdated Wallet, have it pull in hundreds of thousands of blocks and start mining? Also, for this to create a blockchain split, on purpose, one would need at least two wallets. Maybe mine a bit in an intranet, then reconnect to the internet, to mess up the current Slothcoin version 1.3.1b3 network.
Never thought something like this could happen actually. As the majority of nodes all use version 1.3.1b3, Cryptopia and Cryptoguru included. Now I know that it is possible to pull a trick like this off under certain circumstances. But I do not want to make a manual for this procedure. Still it would take a massive effort, lots of mining power and a network to accept such a scheme. But, to be clear, my node should not have taken the longest, split, blockchain. Even though I saw that there might be an update needed for Slothcoin. Just to counter these kinds of scenarios. But this might become a bit tricky.
At first I gave the miner, using the outdated Wallet version 1.2.1, the benefit of the doubt. There was only one IP address with that old version connected and after I went back to a blockchain backup I managed to get control again for Slothcoin version 1.3.1b3, finally. Updated some fora about the badly outdated version 1.2.1 being active and my GPU miner was now on top of things. And I noticed that the old version connected did stay behind. But after a 'getpeerinfo' in the Wallet console I saw there was another one with the same IP address! WOT!? That did not seem like a coincidence anymore. And I know that at least two mining Wallets are needed to get things going that way.
Using a very outdated version, 1.2.1, of Slothcoin, mining with two wallets, connected to two miners, from the same IP address. Then apparantly transfering the mined SLOTH, there must have been a reason to do so. Because it would have had a message bar that stated it was an outdated version that was used. That hit me like a hammer. A blockchain split attack at Slothcoin, why on earth would somebody want to do that? And well, frankly I only care about getting the little Sloth that could going again on the right track.
Luckily there is something that is called a firewall and that did its job perfectly. So, if the one using that outdated version of Slothcoin is not to blame anything but ignorence, than at least it can not do any more harm. That is for the time being. Hopefully somebody wants to take up the community fork and have a go at it. And I will fully support and promote it.
Now I have some SLOTH to give away. And I will do this in 3 portions of 100K SLOTH, currently about 25 DOGE worth. First ones to call, first ones to be served. Just post your SLOTH address in a reply and I'll send 100.000 SLOTH to the first three responders. You may use your Cryptopia Address if you do not have a wallet yourself.
@oaldamster