Zencash an altcoin that uses the Equihash algorithm has fallen victim to a 51% attack. This attack which allows the attack to doublespend and reorganize blocks has been making its way in the news more and more. A possible reason for this is there are more and more Altcoins everyday and the hashrate gets split among all coins, we also have more and more people selling hashpower on places like nicehash allowing a quick and easy move to be made.
Is there anything we can do? Well the Zencash team is asking exchanges to wait 100 confirmations but that would never work in daily life for speed concerned coins, what we need to focus on is stopping the rental power. Hashpower can easily be purchased and quickly moved from pool to pool, currently there is no way to protect against this, if a coin could add denial from nicehash and other hashrate sellers it could help protect itself from this, another measure is to adapt to algorithm changes. Zencash used Equihash which used to be GPU only, recently Bitmain released high speed Asics that decimated GPU miners, without forking to a change this easily allowed a group of machines to take a majority of the network, with GPUs it would have taken more time and cost more.
People complain about the power used by Bitcoins mining infrastructure but this power is exactly what limits a 51% attack, we also know a large part of it is geothermal and hydroelectric (actually helping build out these green industries). Luckily we don’t have to worry about something like this but it does increase fud and fear from non-enthusiest hopefully more will see the faults and failures and learn from them.