Gregory Maxwell

Gregory Maxwell | Man behind Bitcoin Sidechains

Gregory Maxwell is one of the most respected Bitcoin Core developers and former CTO of Blockstream. Greg has contributed a lot to Bitcoin ecosystem and is a key architect in developing the two-way peg that will help Bitcoin implement sidechains. Sidechains will help Bitcoin to have additional blockchains where new features and use cases can be added. Let’s look into Greg’s contribution and his future plans for the Bitcoin protocol

Gregory Maxwell – Skeptic about Bitcoin idea

Gregory Maxwell was initially skeptical about the idea of a decentralized currency. He also thought that this idea is impossible to implement. He was part of the cryptography mailing list where Satoshi Nakamoto introduced the concept of Bitcoin. Greg thought that the idea of Bitcoin won’t work out based on his previous experience working for Wikipedia. Greg even worked for Mozilla before becoming a Bitcoin developer and knows how hard it is to implement a decentralized system.

Greg notably tried to prove in the past that decentralized consensus was next to impossible to implement. But, after days went by and the Bitcoin started to grow, Greg went over the source code and started to learn about it. Then, he concluded that “It isn’t impossible”. After this realization, Greg started to contribute to Bitcoin code by sending his code to Sourceforge (previously people used Sourceforge before Github emerged) where the bitcoin source code is stored.

Origin of Blockstream

Gregory Maxwell co-founded the blockchain technology company called “BlockStream” along with Adam Back, Pieter Wuille, and other developers. The idea behind Blockstream is that there is a tremendous amount of development work to be done on the Bitcoin Blockchain, so they needed an office and funding to facilitate developers to work towards solving the various technical problems and new developments to be rolled out for Bitcoin. Blockstream is the most significant contributor to Bitcoin Core software.

Blockstream is also focused on developing Sidechains, which is an additional blockchain communicating with the main Bitcoin blockchain. New features and functionality can be added to this Sidechain without affecting the main blockchain and also the performance won’t get affected since most of the work can be shifted to the Sidechain. Greg played a significant role in developing the two-way peg which makes Sidechains possible. Developing Sidechains was initially challenging because one-way peg would be problematic and users might end up with useless coins stuck in the Sidechains without being able to go back. Sidechains are very important for the Bitcoin blockchain because Smart Contracts can be run on Sidechains and this feature could help Bitcoin replace Ethereum when it comes to running dApps.

Greg Maxwell leaving Blockstream

Gregory Maxwell announced that he left Blockstream to focus more on Bitcoin protocol and spend more time on developing more privacy features. Maxwell mentioned that he wants more time working independently on deep protocol work. Maxwell wanted to develop cryptographic privacy and incorporate security features into Bitcoin. Maxwell also wants to develop smart contracts on sidechains after leaving Blockstream. Notably, while at Blockstream, he contributed a lot to Bitcoin development. For example, the homographic key generation in BIP32 and trustless privacy-preserving techniques were developed by Maxwell.

Gregory Maxwell mentioned in his departing letter, after working at Blockstream for four years, that he accomplished the goal that he had in mind before joining the startup. His goal was to address the “Significant under-investment” in Bitcoin’s technology and him along with other developers at Blockstream solved it by working together in this company.

Developing Smart Contracts on top of Bitcoin

Gregory Maxwell focused more on developing Smart Contracts on top of Bitcoin after he left Blockstream. In January 2018, he published a paper called Taproot that improves the privacy of MAST (Merklized Abstract Syntax Tree) which helps in enabling Smart Contracts. MAST allows for smaller transaction sizes, more privacy, and larger smart contracts. Later, Maxwell released another paper called Graftroot that enables even more features on MAST.

Below is what Maxwell has to say about his new development that improves the functionality of Bitcoin further

“I expect every transaction to eventually use these tools, at least in limited ways. They are an incremental improvement, making things that were already more or less possible more private and efficient. They replace or make much better things like MAST.” 

Maxwell has added additional privacy features for MAST in the form of Taproot and Graftroot.  Both the proposals will help in implementing Smart Contracts with low transaction fees and more privacy. Taproot and Graftroot will help in making complex applications easily accessible by the average person using Smart Contracts.

The Bitcoin community is blessed to get a unique and a highly talented developer like Greg Maxwell. He should continue contributing more to Bitcoin and help in making the technology so robust that the entire world adopts it as an alternate and an efficient monetary system. We wish him all the best in all his future endeavors.


  1. Complete and utter rubbish. Greg Maxwell is a toxic individual who helped create damaging division in the Bitcoin community.

    1. That’s an opinion. Not an established fact.

  2. January 2018, he published Taproot

    1. Thanks for sharing. Feel free to contribute more to the discussion.

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