Andrew Stone from Bitcoin Unlimited has proposed OP_GROUP as a method for implementing representative tokens – also called “colored coins” within the Bitcoin community.  But some members of the development community are urging caution and more time to decide whether OP_GROUP should be added to Bitcoin Cash software implementations.  Recently, Jonald Fyookball published a thoughtful piece explaining why OP_GROUP is potentially dangerous, and should only be activated after taking appropriate “time to test and analyze extensively” its impact. Fyookball’s post has generated significant favorable reaction from the developer community on Reddit.

May 2018 upgrade is too soon and mining hash will not support this proposal

At first glance, the OP_GROUP proposal appeared to be a small change, given that the opcode is comprised of only 50 lines of code. However, OP_GROUP is capable of changing the Bitcoin design at a fundamental level. It alters how unspent transaction output (UTXO) sets are interpreted and makes token validation a function of miners, in stark contrast to other solutions where this validation is not part of the base bitcoin code.

For other op codes, the script runs only inside the script interpreter, acting like a firewalled black box.  But OP_GROUP changes the way transactions are interpreted outside the interpreter, and thus interacts across the boundary between the interpreter and the rest of Bitcoin.  Because OP_GROUP crosses that firewall boundary, it merits sufficient testing and analysis to ensure it is safe and does not change the very nature of Bitcoin in an undesirable manner.  There is not sufficient time before Bitcoin Cash’s May 2018 protocol upgrade to fully conduct reasonable testing and evaluation of OP_GROUP.

Furthermore, OP_GROUP could product negative impact on the Bitcoin Cash ecosystem.  The opcode would make the miners more responsible to ICOs, which could lead to possible legal issues globally with governments shutting down miners they believe are too involved in the ICO process, much like how exchanges have been continuously targeted in countries like China.

This is why the proposal needs to be examined more thoroughly, taking into account the effect it could have on miners, incentive models, and even other changes that could happen in the future. Pushing for a May 2018 implementation, sans tests and sufficient documentation, is too soon.  The proposal, after all, is a radical change for Bitcoin Cash and for these reasons the mining hash will not support the OP_GROUP proposal at this time.

Note: Tokens in the SegWit chain are referred to as SegWit1X (BTC) and SegWit Gold (SWG) and are no longer Bitcoin. Bitcoin Cash (BCH) is the only true  Bitcoin as intended by the original Satoshi white paper.  Bitcoin BCH is the only public block chain that offers safe and cheap microtransactions.