Announcing Cobra Client: a safe implementation of the Bitcoin Cash protocol and November hard fork

3 min readAug 23, 2018


Bitcoin Cash has a scheduled regular hard fork every 6 months. Hard forks can be a good way to upgrade if consensus is easy to achieve, and this has worked out well for Bitcoin Cash so far. However, the proposals recently released by different Bitcoin Cash development teams for the scheduled November hard fork and committed too by a portion of the hashing power will conflict with each other and lead to a critical consensus failure and split of the coin into two competing chains (Bitcoin Cash ABC & Bitcoin Cash nChain/Coingeek).

Such a consensus failure will be a disaster for all investors and users of Bitcoin Cash, but it is almost impossible to avoid at this point as all the developers and miners involved refuse to back down. Such a scenario will wipe out huge amounts of value from Bitcoin Cash, lead to total ridicule of the currency, and widespread loss of trust and faith. Such reputation damage is simply not worth it, all just so some developers and miners can avoid having their egos bruised around some mostly unimportant and non-urgent changes. Even a temporary fork will cause lasting damage.

I am therefore announcing Cobra Client, a safe and reliable implementation of the scheduled November hard fork. The hard fork implemented by Cobra Client will make no consensus changes or add any new features as it’s clear there is not enough consensus on issues around the new OP CODES and Canonical Transaction Ordering. Instead, Cobra Client will implement replay protection to prevent Bitcoin Cash transactions being replayed across alternative chains. This means users will be unaffected by the forked chains and drama of Bitcoin Cash ABC (BCA) and Bitcoin Cash nChain/Coingeek (BCN) chains and respective tokens.

In effect, Cobra Client implements a version of Bitcoin Cash that is not impacted by any of the controversial new features or chain forks and respects all of the existing features and established consensus. Having replay protection also makes it possible to safely sell BCA and BCN tokens without affecting your existing Bitcoin Cash holdings. Widespread adoption of Cobra Client allows Bitcoin Cash to continue servicing businesses and retail without interruption or failure as one would expect from something claiming to be the equivalent of digital cash.

At the time of writing, the following has been secured to make Cobra Client a viable and functioning implementation of the Bitcoin Cash protocol:

  • A commitment equivalent to at least 25% of the existing Bitcoin Cash hashing power backing the upgrade
  • A number of major businesses currently testing the upgrade ahead of further announcements
  • Continued use of the “BCH” ticker symbol agreed with a major cryptocurrency trading platform, pending success of the hard fork
  • Replay protection already implemented and ready to roll out for a number of SPV wallet clients

For businesses, the best way to avoid a chaotic situation and have uninterrupted service to customers is to run the Cobra Client software in November. Investors and users of Bitcoin Cash should run Cobra Client to prevent Bitcoin Cash splintering into two competing chains, and preserve their existing Bitcoin Cash holdings and avoid getting it replayed across multiple strange chains.

Users of Cobra Client should be wary of competing chains claiming to somehow be the real Bitcoin Cash even as they push dangerous changes that don’t have consensus within the Bitcoin Cash community. When there can be no consensus, the best option is to make no change at all, which is exactly what Cobra Client does in a safe and responsible way. Cobra Client is currently undergoing testing and pending release within a few weeks.