In Polkadot’s case, it was because the long-awaited brainchild of Ethereum co-founder Gavin Wood had finally launched on mainnet after three years in development.
In contrast, Ardor launched nearly three years ago in January 2018. However, this year, it has gained adoption for several notable use cases, including by the Austrian government for two projects. One is to develop a gamification solution for a sustainability initiative aimed at recycling waste heat back into the energy grid. Ardor has also proved its value in the fight against the global pandemic, working on a solution for authenticating COVID-19 tracking data to help Austrian citizens get easier access to virus tests.
For its part, Polkadot is also attracting significant interest from application developers looking to benefit from its interoperability promise. However, what’s going on under the hood of these two projects, and can a three-year-old veteran platform stand up against a newcomer?
History of Ardor and Polkadot
Swiss blockchain firm Jelurida operates Ardor. The co-founders of Jelurida, Lior Yaffe and Petko Petkov, worked on the core development team of the Nxt blockchain, which was first launched in 2013 and is still running without interruption to this day.
Together with a third co-founder, Kristina Kalcheva, Yaffe and Petkov founded Jelurida in 2016. The firm went on to launch Ardor and its first child chain Ignis, in 2018. Since then, the company has worked on building out the ecosystems around its platforms, focusing on enterprise adoption.
Polkadot was developed by Dr. Gavin Wood, one of the original co-founders of Ethereum and the author of the Solidity programming language. The platform has been developed by Parity Technologies, which is led by Dr. Jutta Steiner, who served as Ethereum’s original security chief. Dr. Wood left Ethereum in 2016 and started working on Polkadot in 2017. It launched in May 2020.
Both Ardor and Polkadot aim to solve the challenges of legacy blockchain platforms like Ethereum. Both use a multi-chain architecture that increases throughput via parallel processing. However, there are some differences in the way that they approach the challenge.
Ardor – Parent-and-child
Ardor uses a parent-and-child chain approach, with Ardor as the parent chain responsible for securing the network and overseeing transactions on child chains.
All of the operational transactions are performed on child chains. The child chains are interoperable with one another and can use their own tokens. Ardor ensures ongoing scalability without the need for significant system upgrades by using a system of transaction pruning. This groups child chain transactions together and provides a proof of them to the main Ardor blockchain, after which they’re pruned. Therefore, nodes operating on Ardor don’t need to download the entire history of the blockchain to operate, while they can still verify the validity of each transaction. The approach works in contrast to platforms like Ethereum, which depend on every transaction being traceable back to its first origin.
Polkadot – Heterogeneous Sharding
Polkadot also operates a multi-chain structure, which it calls heterogeneous sharding. The Polkadot main chain is called the Relay Chain, and the sub-chains, or shards, are called parachains. Polkadot is aiming to be fully interoperable, meaning that in principle, any other blockchain can connect into the Polkadot architecture as a parachain, using a mechanism called “bridge parachains.” As the platform is still relatively new, Polkadot’s interoperability is still largely in development.
Full nodes running on Polkadot are also pruned, as they only operate on information contained within the last 256 blocks. However, Polkadot uses archive nodes to store the pruned history and enable anyone to query past transactions.
It’s not fully clear what happens when the archived data reaches a point where it’s prohibitively large to download. The Polkadot Wiki states that Kusama, Polkadot’s “sandbox” network, is around 15-20 GB of data after 1.6 million blocks. Given that Polkadot claims it can scale to a potentially infinite number of shards, the blockchain’s size could increase significantly.
Nominated Proof of Stake vs. Pure Proof of Stake
Ardor operates a pure proof of stake consensus model. It’s based on the same model used by Nxt, the pioneer of proof of stake, which has been operating securely since 2013. In contrast, Polkadot operates its own new consensus methodology called Nominated Proof of Stake. It’s a variation on delegated proof of stake, which has faced criticism for being too centralized due to an upper limit on the number of validators who can participate. Polkadot sets this limit deliberately high to avoid centralization.
Perhaps the most significant difference between the two is the slashing penalties that Polkadot applies. Slashing is designed to deter malicious actors by taking a share of their stake if they act against the interests of the network.
Because it’s a new protocol, it appears that the developers are still working through some of the issues where validators are being penalized for relatively minor issues that can hardly even be described as misdemeanors. In August, one validator was slashed and “chilled” (ousted from the network) for having been offline for 14 hours.
In contrast, Ardor doesn’t operate any slashing model. Given the network has been operating since 2018 without issue, it indicates that perhaps slashing is an unnecessary rule that could deter participation.
Finally, without going into a list of all the applications on each platform, it’s worth a closer look at the differences facing developers looking to build on Ardor and Polkadot.
Polkadot offers developers Substrate, an open-source framework for building configurable blockchains. There’s out-of-the-box functionality that allows any developer in coding languages such as Rust, C++, and others to develop smart contracts and customize the core functionalities of the standard Substrate blockchain. In this sense, Polkadot is very much “the developer’s blockchain.” Anyone wanting to build on it needs at least a foundational technical understanding.
Ardor offers users access to its main child chain, Ignis. Unlike building a customized child chain from scratch, users can take advantage of ready-made functionality on Ignis, including a coin and asset exchange, a marketplace, a data cloud, a voting system, and more. If users need more customization or want to deploy multiple functions, they can set up their own public or permissioned child chain.
Because Ardor is operated by Jelurida, users can also tap into the company’s extensive development experience. Jelurida offers advice and consulting services for users wanting to participate in the Ardor ecosystem. This makes it particularly attractive to enterprise users, even SMEs, who don’t have blockchain development experience.
At first glance, Ardor and Polkadot appear to be similar in that they both operate a multi-chain architecture that aims to overcome the challenges of their predecessors. However, even without going into the technicalities under the hood, it seems likely that Polkadot will ultimately gain adoption by a different user base than Ardor. While Polkadot is taking aim at Ethereum’s user base of developers and DeFi enthusiasts, Ardor is squarely targeting those interested in furthering blockchain adoption for use cases more firmly rooted in the real world.
Therefore, it doesn’t seem likely that newcomer Polkadot poses any immediate threat to the more established Ardor. Instead, it seems likely that both platforms can exist side-by-side in the longer term, gaining users within their respective target audiences.