Ark vs Aion

I want to discuss the similarities and differences between Ark and Aion. Both of these projects have a lot of discussion surrounding them, but little of it goes past “blockchain bridges”. So, lets talk about the two and see what can come of it.

First, Ark:

What is it? Ark is developing “ARK SmartBridges”, which will eventually allow communication “among validated bridged blockchains w/ the ability to perform tasks and advanced functions”. Examples of connected blockchains are Bitcoin, Ethereum, Lisk, and a few gaming tokens. The bridge itself will be the Ark Blockchain, which is governed by an underlying token running on delegated proof of stake (the same as that developed by Bitshares). Ark is positioning itself as connecting to various tools and networks rather than just blockchains. These include: Offchain tools, IPFS, IPDB, Card networks, and optional anonymization.

Now, Aion:

Aion focuses much more on being a blockchain to bridge others and provide governance as opposed to Ark’s mission of developing a community and limited set of functonality to bridge blockchains. Aion will be providing a protocol standard for blockchain systems to communicate. They hope to create one contiguous “value chain” with no off-chain transactions needing to happen. Aion will be the third party between blockchains, freeing each chain up from contentious situations that may result from the use of hubs.

Technical Details of each:

If you are still reading, I will dive into the technical details of each and provide additional insight in their operations. Think of this section as a summary of their whitepaper with some focus on what I think are important details.

Ark

Ark Blockchain

Delegated Proof of Stake:

51 active forging delegates selected by built-in vote system

125 million ARK- Seeded Genesis Block

Multi-sig

Constant block reward

Predefined inflation rate starting at 6.31% and falling to 4% by 10 years out.

8 second block time and 25 transactions / block (can increase in soft fork)

Routing tables and data field for use in bridging blockchains

Scalability upgrades

Increase number of forging delegates

Increase # of transactions / block

Essentially, the idea they have for SmartBridges is fairly simplistic: Have each blockchain or service that wants to connect to it implement an “Encoded Listener”, a daemon that listens for triggers from their SmartBridge and can read its messages. The SmartBridge will be a transaction w/ a filled in data field (the SmartBrdige data field) w/ specialized instructions like “move 2 ETH into account A, and 5 into account B, and take 4 from C and put it into D”.

Aion

Far more details were provided in Aion’s whitepaper, and as a result this section will be longer and more summaries, less details will be provided.

Connecting Networks (networks that facilitate interchain communication and transactions):

They define the following as the responsibilities a connecting network should provide:

Route messages between diff. Networks through common protocol. This includes translation and propagation of message ie move this message on your chain (after translating it) Be secure and decentralized Provide a bridging protocol

This API is very flexible and much more powerful than Arks in my opinion. This is very similar to BGP, a networking protocol that was designed to connect different Autonomous Systems (and is used today to connect the internet together). The idea behind this protocol is to provide purpose-agnostic relays that abstract the complexity of communicating between chains. Rather than having ETH and BTC connect directly, then decide LTC should also be connected to each, just have LTC connect to BTC and BTC can route to ETH as long as it implements the API described above.

Transactions between chains

The format is as follows -

Payload data Metadata about fees, routing, etc Merkle Proof, only used when the sender wants to bypass the bridge. Explanation will come further down.

How does Routing work?

Each node in the route will validate and reach consensus on forwarding / rejecting the transaction. Similar to ping hops, a series of confirmations will be sent backwards after the transaction moves forward.

So, A can send to C through B and on receiving the payload, C sends a confirmation to B and B routes that to A. This part of the design is not fully fleshed out and under consideration so it is subject to change and additional details will become available later.

These transactions will go from sender to connecting network via a bridge, which is a protocol that has two responsibilities: sign and broadcast the transaction if and only if the transaction is sealed and fees are paid and to inform the connecting network of hash updates. Each connecting network must register their directly- connected bridges. These bridges require a minimum stake to operate.

Current blockchains are not compatible w/ Aion. In order to be compliant you must:

Be decentralized and support atomic broadcast and transactions.

Recognize interchain transactions as different from regular ones

Be aware of the bridge’s consensus protocol and store valid transactions

Implement locktime: a feature that allows the network to hold a tokens for a period of time

Tidbits

Nuco will be the first compliant network and Ethereum is discussed as a possible compliant network in the future (given some modifications).

Aion-1 Blockchain will be the genesis implementation of a connecting network.

It also provides a connecting network consensus and bridge consensus mechanism as well as the AVM (Aion Virtual Machine) to allow for running applications on top of the blockchain similar to ethereum.

The rest of the paper discusses the Aion-1 blockchain in detail: specifically its incentive structure, how it will nominate validators, deliver consensus via Reputation, and how the AVM might look. These details are a good read but perhaps too deep in comparing this project to Ark.

To conclude, both of these projects look to provide a bridging solution between blockchains. Ark’s is much broader (and sparser in details) and aims to provide a bridge for blockchains and offchain tools, while Aion is a protocol first approach to creating a standard for the space, very similar to how BGP and networking infrastructure currently routes traffic between AS’s (or blockchains in this case).