Bitcoin Cash hardfork confirmed

November 13 Bitcoin Cash hardfork rumors confirmed by the developers team: here is the fork, the algorithm and mining difficulty details
31 October 2017   697

Hardfork

The previously announced Bitcoin Cash hardfork is to be held on Monday, November 13, so that the exchanges, wallets and other software need to upgrade before this date.

As the developers team reports, the original Bitcoin Cash “EDA” allowed Bitcoin Cash to survive as a minority chain but produces wild fluctuations of hashrate, that in its turn prevents consistently fast confirmations for users, and radically shifts the coin issuance schedule.

After careful consideration, we have made the decision to implement a proposal from Bitcoin ABC lead developer Amaury Sechet. Our decision to choose one specific proposal was not easy, because Bitcoin Cash has several independent development teams, and there was a great deal of deliberation between developers from the different groups.
 

Bitcoin Cash developers team

As detailed, two impartial and unconnected testing teams were chosen to work on the algorithm: Bitprim and nChain. These teams conducted their tests separately and came to the same conclusion of which algorithm was most appropriate. 

However, not everyone thinks so. Charlie Lee, Litecoin creator, doubted the transparency of the choice made:

Algorithm and mining difficulty

According to the team, the new DAA algorithm seeks to accomplish the following objectives:

  • Adjust difficulty to hash rate to target a mean block interval of 600 seconds
  • Avoid sudden changes in difficulty when hash rate is fairly stable
  • Adjust difficulty rapidly when hash rate changes rapidly
  • Avoid oscillations from feedback between hash rate and difficulty
  • Be resilient to attacks such as timestamp manipulation

As the developers detail, the algorithm is based on a 144-period simple moving average. The difficulty is adjusted each block, based on the amount of work done and the elapsed time of the previous 144 blocks.

To compute the difficulty, the process begins with the three topmost blocks, and the one with the median timestamp of the three is chosen. Then, the process is repeated with blocks 144, 145, and 146 (blocks of 144-146 height less than the current) and a median timestamp block is again chosen from those 3.

​From these 2 blocks roughly 144 blocks apart, W is defined as the amount of work done between the blocks, and T as the elapsed time between the blocks.  A high-low filter is applied so that T has maximum value of 2 days and a minimum value of .5 days.  This prevents difficulty from changing too abruptly. (Normally 144 blocks takes approximately 1 day).

Wn = W * ExpectedBlockTime / T .
G = (2^256 / Wn) - 1

According to the team, this is the difficulty target.  

Activation of the new consensus rules will be done on a median time stamp basis on blocks that occur after timestamp 1510600000, which corresponds to November 13th, 2:06 PM GMT.

Athena Bitcoin adds Bitcoin Cash to its ATMs

Athena Bitcoin adds support for Bitcoin Cash to their machines
19 February 2018   72

Rising interest in Bitcoin Cash has made a big impact on cryptocurrency market and service providers alike. The rising exchange rates and more widespread support on exchange platforms contributes to the fact. And this can;t be ignored by companies involved in Bitcoin ATM business. They wouldn't want to be left on the side in such a quick-rising market. So Athena Bitcoin took a logical step and added support for Bitcoin Cash to their ATMs.

In the case of Athena Bitcoin, it's an interesting step because of many reasons. The don't plan to drop Bitcoin anytime soon, so it's just an expansion of bases, rather than a complete turnover. Also added support will be interesting to statistics, because Athena's widespread coverage in several US states will allow to see, whether or not BCH is more popular than BTC in some states.

Bitcoin Cash support will also allow for BCH to fiat conversion with two-way machines available in Athena's network. Added competition doesn't thrill Bitcoin Core community, but BCH enthusiasts are quite happy with this situation.

So far Athena Bitcoin is one of the first providers to give such opportunity to the masses, so it would be interesting to see if other ATM networks will follow the example. Decisions like that are always more than a little controversial so we'll have to wait and see if it pays off.