Bitcoin will change its difficulty every 2016 blocks, and it depends on the average time taken to find a block thus adjusting the difficulty to be higher or lower. Bitcoin set the time to find each block, should be in interval of 10 minutes. So for 2016th blocks, it typical last for 2 weeks. 2016 / (24 x 60min) = 14 days.
EDA was born to solve the problem of high difficulty inherited from the bitcoin legacy after forking. If not, not a single miner willing to mine it since its so unprofitable, except those miners which are ideological driven. So bcash developer introduced this rule in order to lower the difficulty :
Median Time Past of the current block and the Median Time Past of 6 block before has to be greater than 12 hours. If so, it gets 20% easier to create proof of work. In other words, miners can find blocks 20% easier.
Miners exploited this rules and prolonged the mining process by more than 13 hours just to bring down the difficulty of Bcash while ignoring us the user of Bcash. Thereby reduce the work needed to mine a block by 1/4
The proof :
Notice how long it took to mine consecutive 6 blocks ( from 478577 to 478582) , more than 13 hours needed. Miner deliberately did that in pursuit of 6 times of difficulty adjustment!
Impact
This present trends in block time :
Notice how wildly fluctuating block time of BCH compare to BTC. Ranging from as high as 205 to 5.8minutes, while BTC almost constantly at 10min block time (blue is bitcoin and red is BCH)
Sources : https://bitinfocharts.com/bitcoin%20cash/confirmationtime-btc-bch.html#1y
What's bad about this?
Wildly fluctuating difficulty produce the phenomena of "coin-hopping attack". It means miners are free to hop to any pool that promises them higher earnings, which is its rival BTC. This back and forth hopping directly impact on the performance of transaction on Bcash. When the difficulty is too high, confirmation of transaction will take a long time as there are less miners. And while the difficulty is too low, inflation will occurs. As more BCC are mined into market circulation. This further decreases the value of BCC as a transactable currency.
Arguably, an even bigger problem is that because of this dynamic, Bcash mining rewards — new coins — enter the system much more quickly: currently about four times faster than they are supposed to. As a result, Bcash’s inflation rate is relatively high. While Bitcoin’s current yearly inflation rate sits at about 4 percent, Bcash’s yearly inflation rate is on pace to be closer to 16 percent. This favors miners who earn these coins — at the cost of coin-holders.
Sources : bitcoinmagazine.com
Inflation also leads to block halving arrive much earlier! This is where the paradox come. Bcash set its goal on low transaction fee compare to BTC or even zero Tx fee, but reduction of block rewards will directly mean higher transaction fee just to compensate for the loss. Unless, BCH manage to increase ginormously in price, so that the block reward can shrink significantly. But by the way it's growing right now.. It's highly unlikely.
Other than that, Bcash EDA is also detrimental to it's ecosystem. Malicious miner might take this opportunity to prevent adjustment from kicking in. Making it difficult for everyone to mine the coin. Thus producing what we called 51% attack. This loophole must be fix, so that the stable equilibrium can be achieved instead of constantly oscillating between block reward and inflation.
Hope you guys understand the flaw in Bcash so far. If you like it please do the following, upvotes will really be appreciated as much hard work was poured into this. Thanks!
