Interview with Lior Yaffe: Co-founder & Lead Developer at Ardor

Last updated: Mar 30, 2023
15 Min Read
AI Generated Summary

Ardor (ARDR) is a Blockchain as a Service (BaaS) platform that is developing a unique parent-child chain architecture. It launched its main-net in January of 2018.

The project was actually born out of extensive work that was done on the time tested NXT platfom. The developers wanted to improve on the NXT blockchain by reducing blockchain bloat, increasing scalability and eliminating customisation issues.

We were quite intrigued with the Ardor project and its technology so we decided to reach out to their team and ask them some additional questions. Their lead developer, Lior Yaffe, was happy to answer these questions.

Lior Yaffe Interview

Lior Yaffe Jelurida
Lior Yaffe at the 4YFN conference.Image via Jelurida

As the co-founder of Jelurida, Lior Yaffe is not just the Lead Developer on Ardor but he is also the dev lead on all of their other projects. These include the likes of NXT etc.

Therefore, he is perhaps one of the best people to speak to about the technical aspects of Ardor and the broader vision of multi-chain architecture systems. Below is our interview in full:

On Yourself and Jelurida

How and when did you get involved in blockchain engineering?

I started programming at the age of 13, learned computer science at university, and worked for almost 20 years as a professional software engineer for mainframe integration products (nothing to do with blockchain). I started coding for Nxt back in 2014 as a hobby and gradually made it my full time job.

What spurred the formation of Jelurida and the eventual launch of your first blockchain project, NXT?

Jelurida was formed in 2016, back then, Nxt was being cloned at a rapid rate and it led to concerns for our community to distinguish between legitimate projects and opportunistic ones so we felt the best way to deal with this was by forming a legal entity and a new type of licensing agreement, the JPL, to protect the software and the security of our users.

Forming the company also provided legal protection for our blockchain developers and gave us an opportunity to raise money to fund the long-term development.

Much of the inspiration and development behind Ardor came from challenges you faced with NXT. These included things such as Blockchain Bloat, Single token chain and particular customisation issues. Were there any other challenges you encountered with NXT that helped inform your development of Ardor?

The challenges you mentioned are not specific to Nxt, they are inherent limitations of pretty much any other single blockchain product. Of course, working with developers and entrepreneurs on Nxt based projects back in 2014 and 2015 provided our team a unique perspective on the limitations of existing blockchain solutions, such as the need for end users to pay transaction fees, the need for every node to process every transaction, and the awkward design of most smart contract platforms, just to name a few.

On Ardor

How did you come about the child chain solutions on Ardor? How are these different to side chains that have been developed by other projects?

In early 2016 it became apparent that for blockchain technology to reach mainstream adoption, a new architecture would be required in order to enhance the single chain design. Child chains are the unique Ardor solution.

In a nutshell, it uses a parent chain for proof of stake consensus while off loading the actual decentralized applications to multiple “child chains,” which inherit their security from the parent chain. This is all part of the same product. On the contrary, side chain solutions, such as the ones often discussed in the context of Bitcoin, are a workaround.

The devs say, “we can’t change bitcoin so we’ll find some kind of a workaround to peg something else into it.” Many other projects announced side chain solutions, but frankly, I haven’t seen any other multichain architecture in production on a public main net except Ardor. Nothing has come even close to what we have in production - and we have had it for more than a year.

Let’s talk about Ignis. Has it been a great Proof of Concept for Ardor child chains?

Ignis is the first, and to some extent, the “core” child chain of Ardor. It provides all the functionality of Nxt and more. Ignis is the chain used for deploying lightweight smart contracts, issuing assets such as NFTs (called “singleton assets” in Ardor), and performing any account specific transaction, such as setting account properties or account control, which is an advanced form of multisig account.

Unlike other child chains, it is entirely public and permissionless - so anyone can create an account and build a decentralized application. While Jelurida does release new features for the Ignis child chain regularly, the company does not have any control over who uses and builds on Ignis.

So far, Ignis has not enjoyed widespread adoption, but I expect that once we get broader adoption of the Ardor platform as a whole, and lightweight contracts specifically, the market will start to have a deeper appreciation of the importance of Ignis - driving more demand for the IGNIS token.

Lightweight Contracts Ignis
Image Source: Ardor

Apart from Ignis, you have a number of other projects that have built on Ardor already. Which of them are you particularly excited about and why?

This is another area where, thanks to observations of the market and lessons learned from Nxt, we have differentiated ourselves from other projects. Ardor child chains are created by Jelurida based on an agreement with the child chain management entity.

Therefore, we make sure that each child chain of the Ardor platform has a substantial and well-thought business case behind it. AEUR provides a fully operational Euro pegged token and fiat gateway, BITS represents a group of blockchain veterans developing decentralized applications using our platform, MPG is managed by a group of property investment specialists using the Ardor platform to tokenize real estate.

All of these projects were carefully reviewed by Jelurida before being deployed to production. I think each and every one of them represent a unique example for the future of decentralized applications.

That said, not all projects are being built as new child chains. Tarasca is simply using the public Ignis child chain to run art auctions and digital card games on the blockchain. EZYCount is using Ignis tokens to create an innovative token-as-a-license model for licensing accounting software. It’s exciting to see more and more of these concepts being tested in reality on the Ardor platform.

Following on from the above, are there any project ideas that you would ideally like to see being developed on the Ardor blockchain

Sure. Back in October, we published three coding challenges for real world applications including a decentralized coin exchange, an authenticated cloud storage solution and an on-chain reputation management system. We received some really nice solutions and I would like to encourage the winners to continue optimizing their work.

Going forward, I see Ardor becoming a de-facto standard for hybrid applications, which are blockchain-based while freely interfacing with external centralized services, such as the ones provided by FAMGA companies and the like.

Transaction vouchers look really interesting. Can you explain this concept a bit more for us? Have these been used by any projects as of yet?

Transaction Vouchers are the blockchain abstraction of an invoice and have been available on the Ardor mainnet since August 2018. In the specific case of payment, they represent a digitally signed payment request; however, they can be used for many other use cases such as vote delegations, proof of identity, etc.

The end result is that it becomes nearly impossible for users to send funds to the wrong account address when using transaction vouchers. Currently, we are using them for internal platform bookkeeping, bounty payments, etc.

Soon, we will start to use them for a new account faucet contract. In my view, vouchers represent another essential building block that every decentralized application will need at some point.

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You guys have developed lightweight contracts. How are these different from smart contracts on the Ethereum network for example?

Ignis Lightweight contracts, like Ethereum contracts, are turing complete contracts stored on the blockchain. Unlike Ethereum contracts, lightweight contracts are coded in Java and are not executed by every node.

Instead, our comprehensive security framework provides tools for trustless execution by specific contract runner nodes. Our contracts do not store the contract state inside the contract - instead, their output is standard transactions submitted to the blockchain.

This unique solution provides enormous operational advantages: contract execution does not require gas, upgrading a contract is simple, and using a contract to interface with an external system is supported and encouraged. Not saving state inside the contract also makes our contracts much more secure against hacking.

These lightweight contracts are coded in Java which could be an attractive solution for enterprise systems. Have you received any interest?

We just launched contracts on mainnet a few weeks ago at the start of January 2019. I can confirm that we are working with several large software companies who are reviewing our platform. So far, feedback is great but these are early days.

You guys are conducting research on Zero Knowledge transactions. Could we eventually see these types of transactions implemented on Ardor?

Ignis and Nxt already support a state of the art privacy feature named “coin shuffling,” which is based on a research paper published by German cryptographers. In addition, in one of our next releases, we will introduce a Shamir Secret Sharing based solution for private key protection.

We are currently reviewing ways to integrate an existing secure voting solution based on ElGamal encryption. As a more long term plan, we are looking closely at ZKP, FHE and MPC technologies both in the context of homomorphic signatures to prove execution of lightweight contracts, and as an optimization layer on top of the existing blockchain, assuming we can validate proofs faster than we can validate transactions in a block.

How is blockchain pruning on Ardor going (in the Q1 2019 roadmap)?

Blockchain pruning, representing the ability to remove transactions from the blockchain once they are no longer required, is pretty much implemented. We will deploy it on testnet probably in the first half of 2019 based on development priorities and other commitments to customers.

Anything else we can look forward to from the Ardor project for the rest of 2019?

Absolutely. We will continue to enhance our business logic with customer driven features, like child chain control and additional transaction types to provide better support for Security Token Offerings (STOs).

We are planning to enhance the Ardor wallet with a more user- and mobile-friendly UI, plus we are working to support full node deployment on Android devices to better support IOT solutions. Extensive load-testing and performance optimization will start soon.

Once usage level justifies it, we will move forward with our subnets research - although this may have to wait for 2020. As always, we will monitor new developments in the blockchain industry and adjust our plans accordingly.

The Ardor project has a really engaged and active community around it. How has this helped drive the project forward?

The Nxt and Ardor community provides amazing benefits for our projects. Community members work tirelessly experimenting with our products, promoting us, alerting us when things go wrong or when something needs an urgent response. They bring up great new ideas and provide great feedback on existing ideas - and generally create a very positive buzz around our projects.

On the Broader Blockchain Ecosystem

You have been critical of PoW protocols in the past. What is the biggest problem that you view with these systems? Security? Energy? Scalability?

Energy consumption is a huge problem for PoW chains - especially when considering the fact that it cannot be reduced without increasing the network’s exposure to 50% attacks. As to security and scalability, in my view there is no direct relationship between the consensus algorithm and these factors.

With correct and efficient design, both PoW and PoS chains can scale to the same level while remaining secure - PoS chains simply achieve the same result in a more energy-efficient manner.

What do you think are the biggest challenges to cryptocurrency and blockchain ecosystems currently? How could we most effectively address these?

To gain real world adoption the industry needs to provide a simpler and more secure user experience, as well as better scaling solutions. These are difficult engineering problems but I think given enough time and resources they can be solved. Ardor is already leagues ahead of the competition when it comes to addressing scalability, but we have a ways to go with improving the UX.

More broadly speaking, there are three additional issues the industry currently faces.

First, we need standardization between blockchain solutions, think SQL, XML, and standard APIs to give organizations a choice of platform and the ability to switch in the future - not get locked into a specific platform forever.

Second, we need to provide users better security guarantees. Currently, hackers and scammers are considered culture heroes instead of criminals. Law enforcement agencies are not very effective against these internet era crimes which span multiple countries and continents.

Last, we need government backing.

The most compelling use cases for blockchain are configurations of companies that need to work together but do not trust each other. Competing companies will never implement such blockchain applications on their own when the regulatory environment is unclear.

Governments must acknowledge the legitimate benefits of this technology, provide a clear regulatory environment that lends itself to this technology, and support efforts to establish industry best practices.

What are you personally most proud about when it comes Ardor, NXT or any of the other projects that you have been working on?

I think the Ardor and Nxt projects and the wonderful community backing them represent the sane side of crypto. The people that actually can see through the hype and understand the real technology and its long term potential.

I’m proud to be part of this. In a sense, this is the first time in history that software engineers get to set the rules- this is a massive responsibility and it’s important to constantly check ourselves so as not to misuse this power.

Anything else you want to share with us?

As a blockchain developer in this extended market down-trend, it is most important to think for the long run and continue to advance our product by delivering on the the priorities of our planned roadmap.

The bear market has also given us a chance to engage third parties for an extensive evaluation and revamp of our branding strategy so our products will be ready for primetime when the market turns around.


So it seems as if there are indeed some big plans for the Ardor project on the horizon. The successful launch of the MPG child chain has proven the use case for parent-child architecture.

Of course, there are challenges that are faced by the entire blockchain ecosystem but these are not related to Ardor. Moreover, with the Jelurida developer talent behind the Ardor project, they are likely to emerge as one of the favorable cryptocurrencies when the market turns.

If you would like to keep up to date with the Ardor project then you can follow their twitter account as they are quite active updating the community. If you want to buy ARDR it is available on Binance and Bittrex.

Editorial Team

The Coin Bureau Editorial Team are your dedicated guides through the dynamic world of cryptocurrency. With a passion for educating the masses on blockchain technology and a commitment to unbiased, shill-free content, we unravel the complexities of the industry through in-depth research. We aim to empower the crypto community with the knowledge needed to navigate the crypto landscape successfully and safely, equipping our community with the knowledge and understanding they need to navigate this new digital frontier. 

Disclaimer: These are the writer’s opinions and should not be considered investment advice. Readers should do their own research.

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