What is Polkadot's Shared Security? Security Dashboard — Polkadot Decoded 2022
Explanation based on the presentation by Javier Viola, Santiago Balaguer, Héctor Bulgarini, Alberto Viera and Nicolás Arévalo, moderated by Ezio Rojas.
What is Polkadot’s shared security?
Within the Polkadot and Kusama multichain ecosystem, shared security is one of the key pieces of infrastructure that the ecosystem needs to provide an efficient product for everyone.
Having shared security in a system like Polkadot gives us the security, providing a service so that all parachains can communicate securely and without knowing and trusting each other, effectively realizing Polkadot’s vision.
For one to have a blockchain infrastructure you need to have a security scheme, of what consensus is and how any blockchain works.
In this new generation of blockchain that is being developed, when you start your network you have to have different actors, which specifically speaking in this case are the validators, who are basically the ones that execute all the consensus and all the security around these blockchains that we create.
There are different models of how you can launch your network.
If you look at the example of other networks when you launch your network you have to take care of all your validators and all your setup. Initially, this is not so decentralized in spirit because generally, these networks start under a foundation or a company, so there is a whole process to get these blockchains up and running.
Polkadot provides a whole system of active validators already in operation, and when a parachain (which is a blockchain built in Substrate) connects to Polkadot it automatically has all the decentralization and all the validator scheme that Polkadot has. This is a big change, as it is a great asset because the parachains, through the auctions, can access security as a commodity, because when a parachain executes a block or a transaction, it is validated absolutely by the entire ecosystem of validators.
This brings a lot of benefits because it adds another layer of security to the ecosystem of parachains that are being developed.
How do validators go about this process of securing parachains as a whole within Polkadot?
The protocol validators, what they do to validate the parachains and add this shared security is that automatically these validators are assigned to the different parachains, within the protocol the different algorithms are run for the assignment of the validators to the different parachains. What these validators then do is the first validation through the block of the parachains and then they send a notification to the Relay Chain or to the Include, and the rest of the validators carry out a second validation function where they validate the block that is a candidate of these validators that are assigned at that moment to the parachain.
It is important to note that this is a temporary assignment, that this assignment is constantly changing in the production of blocks, which automatically changes the subset of validators that are assigned to the parachain, and this adds another layer of security.
So, in a way, you have a two-step validation. You have a first validation of the validators assigned to that parachain or subset, which are the ones that also put their staking into play when producing a candidate block, and a second validation of the rest of the validators, which validates that the block can be finalized and generate the canonical block in the Relay Chain.
This is a process that shields the entire protocol and the functioning of the parachains.
Perspective and vision of Moonbeam and Acala, two of the main parachains in the Polkadot ecosystem
How does Moonbean assess this shared security within Polkadot?
For parachains, the valuable thing that Polkadot provides is that they don’t have to worry about the security of block completion, which means that when a transfer is made from block A to block B, Moonbean doesn’t have to verify that the transfer is valid, because that is done by Polkadot. So the parachains can focus on doing what they do and do it effectively, while Polkadot takes care of the consensus part where it guarantees whether a block is valid or not.
Polkadot also gives parachains a deterministic purpose; when Polkadot guarantees that a block is final, there is no going back and the transaction can be sent. However, when using Ethereum we need to wait for x number of blocks to be executed before a block is final and the transaction can be carried out.
What is Acala’s assessment of shared security?
Acala sees Polkadot’s shared security as a benefit, valuing it as the next evolution of blockchain design because it allows blockchain developers to focus on the product and not have to develop the whole set of validators. Acala can focus on the use case, which is that of a centralized finance blockchain and they don’t have to worry about security, thanks to shared security, which is what allows all these blockchains to be connected without fear of the risk of these communications between them.
What does Polkadot offer in the face of the hacking scenario we see in the industry today?
There are blockchains that do not have shared security, such as Cosmos, that have to validate themselves, but they are trying to go down the path towards shared security because they see a clear benefit in using this heterogeneous multichain model. The problem is that doing something like this is very complex when the protocol is not designed this way from the beginning, it is a change that takes a long time. The clearest example is Ethereum, which has been moving from Proof of Work to Proof of stake for a long time.
This gives an advantage to those who develop on Polkadot over other chains because other chains will need several years to achieve similar development.
Analyzing the case of the fall of Terra, at one point there was a situation where the organization decided to shut down all the validators because the economic value was so low that it was very easy to attack the network, and when the network is attacked, there is no turning back. When there is a low economic value, the barrier to attacking the security of the whole ecosystem is low as well. So Terra decided to shut down the validators, a sign of failure because it means that the ecosystem is no longer sustainable in terms of security and functioning. This is something that could not happen in Polkadot because if at some point a parachain collapses economically, it would still have the shared security that Polkadot offers because the validators are detached from the economic case of the parachain. This provides a great layer of security because, in the event of a collapse of one of the parachains, the security of the protocol continues to function through the DOT and KSM tokens.
This is very important because by having a multichain architecture where the ecosystems are connected by bridges when there is a hacking attack or economic attack on one component within the entire network connected to cross-chain it basically affects the entire infrastructure.
What is the future of shared security and are improvements expected?
It will continue to increase in value, which will attract the possibility of greater attacks, i.e. it will be a clearer target for attacks as it adds more value. From a shared security point of view, work is continuing to improve all the use cases, to improve scalability as well, and the idea is to continue with this very high level of security and interoperability of the networks.
Polkadot is a protocol that has been developing for many years in a very consistent manner, but above all with very secure steps, and the network will continue to evolve at the same pace, always improving the service and trying to see how, without compromising security, we can scale the system, both in terms of the number of parachains and the processing capacity between them, and ensure that the parachains can process more and more transactions and that the Realy chain can offer this service faster and faster.
Both the protocol and the game theory and tokenomics are based on shared security, which makes it one of the most important factors in the network. It is a big differential in the industry and is being optimized to be able to scale the protocol.
