In a presentation at the recent Bitcoin Foundation DevCore Workshop at Draper University, Bitcoin Core Developer Greg Maxwell revealed that an official BIP (Bitcoin Improvement Proposal) for adding two-way peg sidechain functionality could be ready in a matter of months. Sidechains is a concept that first became popular in April of 2014 after Blockstream’s Adam Back and Austin Hill discussed the proposal on episode 99 of Let’s Talk Bitcoin.

A working implementation of the decentralized sidechains concept is highly anticipated by the Bitcoin community because it will allow for easier testing and the implementation of new ideas on alternative blockchains without the need to create a new cryptocurrency or altcoin. A test version of sidechains, Elements Alpha, is currently available via a peg with Bitcoin’s testnet token.

Required Code Changes are Not That Complicated

Near the end of his presentation, Greg Maxwell received a question regarding what it will take to implement full sidechain functionality into Bitcoin Core and when that implementation could take place. Maxwell noted that a soft fork is required to bring decentralized two-way peg functionality to Bitcoin. He also discussed the lack of complexity associated with the code that would enable sidechains in Bitcoin Core:

“The change to allow Bitcoin to do the verification of the decentralized peg (not the federated one) is code that’s in Elements Alpha because we use it in that one direction. So, you can look at that and get an idea of how complicated it is. It’s not very complicated; it’s on the order of fifty lines of code and script functionality.”

Because the code is already implemented in Elements Alpha, Bitcoin Core developers and contributors have the ability to see what they do and don’t like about that particular implementation before it is added to Bitcoin Core.

Bitcoin Scalability Debate May Have Delayed Sidechains BIP Release

Maxwell admitted he would have liked to have had an official BIP created for sidechains earlier, but he explained that issues regarding the debate around Bitcoin’s scalability have led to delays:

“There’s no BIP for doing this right now. I would have liked to have had one about a month ago, but with all of the things going on with Scaling Bitcoin and things like that, it’s fallen to a lower priority. I’m hoping to have a BIP out for this in the next couple of months, and then it will take time.”

It could take time for consensus to build around the acceptance of a sidechains BIP, but, in the past, Blockstream President Adam Back has stated, “Generally technical people have been quite supportive of the idea of sidechains and the flexibility it adds for experimentation and extension.” Having said that, Back has also noted that it would be hard to predict a timeframe for consensus to build around a specific proposal.

Delays Were Expected

Another audience member asked Maxwell about how his thoughts on a sidechains implementation have changed over time, and the Bitcoin Core developer explained that there haven’t been any delays that weren’t expected:

“As far as how the scheduling has gone, it’s played out basically the way I thought. It’s not my first time around the bend, so I expected many delays. Looking at it with rose-colored glasses I thought, ‘Oh, yeah. We can have this up and running in a couple of months.’ Then I said, ‘Okay. Add a factor of ten.’ So, I think it’s gone alright, and I’m not really sure what the future holds, but it will be fun to find out.”

There are many interesting, blockchain-based projects currently in the works that could be implemented as sidechains, such as the Ethereum-inspired RootStock and the decentralized prediction market Truthcoin, but these platforms cannot reach their full potential without decentralized two-way peg functionality enabled in Bitcoin. For now, blockchain developers are able to create Bitcoin sidechains under a federated model that does not come with the same low-trust guarantees as proof-of-work-based systems.