From Scalpels to Qubits: The Story of the World's First Post Quantum Block Chain

The following post was written and/or published as a collaboration between Benzinga’s in-house sponsored content team and a financial partner of Benzinga.

For more than a decade, Peter Waterland diligently pursued his role of a surgeon. At the same time, he began delving into a variety of intellectual activities (so much so that he gained a reputation as a polymath). Among these were cryptography, programming and blockchain technology, all of which propelled him to become a passionate cryptocurrency champion.

Peter greatly enjoyed the challenges this new technology presented and made several contributions to the cryptocurrency world as a result, among them a bitcoin bip38 and bitcoin multi-signature wallet and a bitcoin steganography library.

His writings clearly exhibit this passion, as they cover everything from Ethereum economics, to private key encryption. Not incidentally, private key encryption would become his most vexing concern, as he believed it would eventually prove to be the achilles heel of Bitcoin.  

Peter realized that a powerful-enough quantum computer could conceivably undermine the Elliptic Curve Digital Signature Algorithm (ECDSA) used in Bitcoin and other cryptocurrencies. Once achieved, an attacker could reconstitute a user’s private key from their public key and access their private funds. 

In 2016, however, the idea of a practical quantum computer seemed like science fiction to many in the blockchain space. Quantum computers only existed as a handful of qubits, and IBM was a year away from demonstrating any quantum computing whatsoever.  

Peter was convinced that this technology would quickly emerge, however, and that a quantum-proof blockchain would soon be needed.

As he would later assert, “(technological) change comes faster than we expect and often in a non-linear fashion” (The QRL Blog).

Although the threat of quantum computers to the blockchain space appeared distant, several organizations had been preparing for this eventuality.

The first organization to take the quantum threat seriously was PQCRYPTO, a global network of post-quantum cryptographers and related professionals. After ongoing discussions about the threat, the organization recommended XMSS as a post-quantum security solution in March 2015. Several months later, the NSA announced that they were preparing for the quantum-threat. 

Considering this, hash-based signature schemes were viewed as the best way forward, due to their minimal security assumptions. In 2016, Peter wrote and published the first cryptocurrency whitepaper on the topic, along with the project’s name, the Quantum-Resistant Ledger (QRL).

Once this was met with favorable reviews, he began pulling together a core technical team to make his idea a reality.

The Solution

On paper, determining the best digital signature solution to the quantum threat was fairly straightforward. Cryptographers had already asserted that a hash-based digital signature was the simplest and most promising safeguard against a quantum computer.

After all, hash-based digital signatures can resist quantum computers because they rely upon the one-way nature of a cryptographic hash function. That is, they combine user-fed data with another numerical input to produce a fixed length digest as output.

Using hash functions to create digital signatures, however, incurred a major drawback - they could only be used once. He needed a hash-based signature scheme that could be used many times over (either to sign a document or create a transaction).

The answer was a hash-based signature scheme that employed a ‘merkle tree’ (binary hash tree). A merkle tree allows the public keys from many one-time signatures to be concatenated in pairs and hashed upwards in an inverted tree structure to a single root hash.

Ultimately, a hash-based signature scheme named XMSS (eXtended Merkle Signature Scheme) was discovered. XMSS incorporates a merkle tree and can be used many times over. Peter made it the basis for the Quantum Resistant Ledger (QRL) project, the first post-quantum secure blockchain. 

The decision was a critical one, since privacy and security are central to Bitcoin’s value proposition. When Bitcoin security appears compromised, its price drops precipitously. 

Just this month, FBI agents recovered bitcoin from a wallet belonging to the Colonial Pipeline hackers. Bitcoin quickly lost nearly 10% of its value. 

While the on-chain Bitcoin address linked to the Colonial Pipeline ransom wasn’t hacked, the FBI figured out the public key by analyzing on-chain data. When they could link the public key to a particular custodian, they asked the custodian to share the private keys to that address. 

The Journey

As might be expected, the journey from whitepaper to a working blockchain can be ‌arduous. Before mainnet can be achieved, a variety of complementary components to the blockchain must be implemented. For instance, a multi-signature wallet or a secure messaging protocol for QRL’s p2p network are typically desired. 

The QRL core technical team established thereafter was intent on making his vision a reality. 

In practice, that means moving from an isolated private VPS network with a handful of nodes (and under complete developer control) to a public testnet with over 50 nodes spanning the globe. 

And moving from a handful of Raspberry pi’s to high-power Amazon AWS instances. 

As might be expected, this move instigated a host of short-term issues that Peter and his team had to resolve (including temporarily moving to a Proof-of-Work consensus). After extensive effort,  the QRL core technical team managed to move forward with a mainnet launch in 2018.

On the near-term time horizon, QRL is working with Geometry labs to deliver a Proof-of-Stake consensus mechanism, firmly cementing its place in the ranks of second generation crypto currencies.

Geometry Labs is a decentralized finance and cryptography research and development lab.  Although relatively small, the lab specializes in helping blockchain outfits refine their DeFi products and tooling, blockchain infrastructure, analytics and observatories, and development of novel cryptographic mechanisms.

The Community

Along the way, the QRL core technical team inspired several highly-skilled community members to join the project. The ability to do so was critical, as the project was not well-funded in comparison to larger projects.  

They made it a point to recruit team-oriented individuals passionate about the technology.  As Peter once noted, “the project’s strength lies in the solid participation of polite, well-informed and helpful community members.” 

Since attracting developers was paramount, the project made small but noticeable improvements to quell frustration - like creating tutorials and updating APIs to facilitate development. 

The QRL core technical team also instituted a QRL Improvement Process (QIP) on github, allowing anyone to suggest improvements to the existing QRL ecosystem. The space allows safe dialogue between developers and users to occur, such as discussing technical points of view or debating the merits of a particular upgrade. 

As the project grew, a foundation was established to manage its finances and support its development. While foundations are fairly common in the cryptocurrency world, the QRL Foundation has achieved a blockchain with:

• Complete post-quantum secure security and crypto-agility.
• Full Desktop (Windows, Mac, and Linux), Mobile (iOS, Android), and Hardware (Ledger Nano S/X) support.
• An Ephemeral Messaging System.
• Weighted threshold multi-signature transactions.
• File notarisation.
• Full API and Documentation.
• A strong passionate (and compassionate) community.

The Core Team

The QRL project can attribute a large part of its many talented contributors as well. Although relatively small, the team has made great strides within the past two years. 

The project development team is led by its two core developers, Kaushal Kumar Singh and Dr. JP Lomas.  Charlie Thompson, James Gordon, and Adem Bilican round out the development team. 

Project advocates include Jack Matier (Director of Communications), Michael Strike (Director of Outreach, video personality), and Ryan Malinowski (Director of Advocacy).

Finally, project team advisors include Leon Groot Bruinderink (PhD, Post-Quantum cryptography) and Robby Dermody (Co-founder, Counterparty).  

Summary

As you can see, Peter Waterland devoted a tremendous amount of time and effort to make his vision a reality. Indeed, it's unlikely that this project could have succeeded without him. 

In the end, he had more than a great idea. He was able to marry his extensive technical knowledge with team leadership capabilities. 

Today, the QRL project consists of a large and vibrant community and a dedicated team working hard to prepare for a post-quantum future. 

As their division of labor has expanded, however, an active group of insiders has stepped up to help lead the team. Known as The QRL Contributors, this informal committee will be expanding its role in governance... 

This transition is both natural and expected, given the organization’s continued growth and complexity.  The project’s future is bright, as evidenced by its move to establish a development hub with partners in the United Arab Emirates.

Join the discussion about the future of post quantum cryptography today in our discord channel at  https://discord.gg/WFC3knCT8E

The preceding post was written and/or published as a collaboration between Benzinga’s in-house sponsored content team and a financial partner of Benzinga. Although the piece is not and should not be construed as editorial content, the sponsored content team works to ensure that any and all information contained within is true and accurate to the best of their knowledge and research. This content is for informational purposes only and not intended to be investing advice.