It has become challenging for developers to design applications that can handle multiple blockchains. Users prefer using one or two chains because blockchains are resource-intensive. Interoperability was one of the roadblocks to the widespread use of blockchains. Cosmos and Polkadot have emerged as two frontrunners to address this problem. We will compare Cosmos vs Polkadot, and examine their underlying architectures and technologies and the two native currencies and development frameworks.
What is Cosmos?
Let us understand what is Cosmos. Cosmos is an ecosystem of blockchain that focus on scalability and interoperability. Before it came around, blockchains were isolated from each other and unable to communicate. They were challenging to construct and had a low transaction speed. The network uses a fresh technical perspective to tackle these issues. It is a free platform that facilitates interoperability between various blockchains, like Binance Chain and Terra.
The ultimate goal of Cosmos is to establish an “Internet of Blockchains,” a decentralized network of blockchains capable of communicating with one another. It provides the ideal solution for several use cases and allows blockchains to preserve their independence, execute transactions rapidly, and communicate with other blockchains in the ecosystem. The cryptocurrency ATOM fuels and protects the network of interconnected blockchains built to scale.
What is Polkadot?
Let us focus on what is Polkadot. Polkadot is a blockchain that connects blockchains, enabling the transfer of data and assets between two incompatible blockchains. It aims to be quick and scalable. The blockchain uses DOT cryptocurrency for governance and staking.
Polkadot is like a network of networks that enables communication between different blockchain designs. It achieves this using parachains or modified blockchains with unique features and tokens.
The network was modeled around the Ouroboros protocol and utilizes the nominated proof-of-stake (PoS) consensus process.
1. Blockchain architecture – Cosmos vs Polkadot
Let us compare the difference between Cosmos vs Polkadot based on their architecture, in Polkadot the relay chain is the main, and all other chains are known as parachain, while in Cosmos the main chain is the hub, and all other connected chains are called zones. The Polkadot architecture uses the principles of the sharding concept, and it aims to address the scalability and interoperability issues that plague many current blockchain-based applications. The Cosmos blockchain architecture follows replicated deterministic state machine.
In Cosmos Architecture, the central chain is called a hub and it connects to other blockchains knowns as zones. Each zone has its validator community to preserve its state. When a zone, wants to communicate with another, it uses Cosmos IBC to send packets. The hub tracks the balances in multi-token ledger balances.
The zones use light status to keep an eye on the Hubs status, but the hub does not monitor the zone status. Zones implement the IBC interface and use a deterministic finality algorithm (Tendermint) to send messages to other chains through the hub.
Cosmos uses peg zones (similar to bridged parachains) to communicate with external chains.
The architecture of Polkadot Blockchain
Polkadot architecture has a Relay Chain that serves as the system’s main chain on Polkadot, and all validators are on the relay chain. The collators build and suggest parachain blocks to validators. They do not have any security obligations and hence do not need a strong incentive structure. Collators can submit one parachain block for every Relay Chain block every six seconds. Before committing a block to the main chain, validators do several availability and validity tests before committing to the final chain.
Since parachain slots are limited, the parachain candidates bid in an auction to secure a spot for two years. Polkadot has the option of parathreads for parachains that lack resources or the requirement to run in a six-second block of time and operate on a pay-as-you-go model where you pay to execute a block when required.
Polkadot uses bridge parachains that provide two-way interoperability to communicate with chains that want to use their finalization method.
2. Consensus mechanism on Cosmos and Polkadot
The consensus mechanisms of Cosmos and Polkadot are different. Cosmos supports the consensus algorithm that complies with the ABCI specification (Only Tendermint follows this specification). It gives validators the option to accept or reject a single block. Block production and finalization follow the same pattern, and only one block can be finalized at a time.
Polkadot uses The BABE (Blind Assignment for Blockchain Extension) hybrid consensus algorithm, which combines the verifiable random function and Ghost-based Recursive Ancestor Deriving Prefix Agreement (GRANDPA) (VRF). Grandpa’s consensus method moves swiftly and accepts several validators ( 1000 validators). Every block does not require a vote from the validators. The algorithm accounts for the block with the largest number of votes before passing it on to the ancestors. The supermajority vote block’s decisions become binding.
The Cosmos consensus or Tendermint consensus is a round-robin technique that enables finality and is used by the hub and zones. The algorithm creates and finalizes the blocks one at a time because block production and finalization follow the same path. It has quadratic transport complexity because it is a PBFT-based method (like GRANDPA), yet it can only finalize one block at a time. The Tendermint algorithm creates finality for each block by having each validator communicate with one another to approve or reject each given block. The algorithm has undergone live stress testing with 200 validators and 6-second block durations during Game of Stakes, and it is quick.
Polkadot consensus mechanisim
Polkadot uses a hybrid consensus protocol that has two subprotocol: BABE and Grandpa collectively called Fast Forward. BABE (Blind Assignment for Blockchain Extension) uses a verifiable random function (VRF) to assign slots to validators and a fallback round-robin pattern to guarantee each slot has an author. Grandpa (Ghost-based Recursive Ancestor Deriving Prefix Agreement) votes on chains rather than individual blocks.
This has several advantages – it reduces the complexity of transport for block production and finalization. Due to BABE’s linear complexity, scaling to thousands of block producers is simple and involves little networking overhead. GRANDPA is quadratic in complexity, but its execution time, or the number of blocks it finalizes in a batch, reduces it by a factor.
Second, it gives the flexibility to add unfinished blocks to the chain and lets additional validators carry out thorough availability and validity checks to ensure that no invalid state transitions enter the final chain.
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3. Governance & Membership – Polkadot vs Cosmos
If we compare Polkadot vs cosmos blockchain, we find they have different governance and membership criteria. Polkadot follows multicameral governance i.e. a proposal passes through multiple houses before it becomes a rule. Cosmos has coin-vote signaling and uses coin-vote for passing referenda. In Polkadot, validators are not given any voting power based on who nominated them.
The Cosmos governance model uses coin-vote signaling to pass referenda. Similar to other blockchains, governance implementation occurs via a protocol split. All token holders are eligible to vote and in case a delegator chooses not to vote, the validator they designate will act in the capacity. There is no single governance process in the Cosmos network. There is no single set of guidelines governing the network of blockchains, and each hub and zone has its governance procedure. Anyone may submit a text proposal to the Cosmos Hub under a set of regulations, and Atom holders can vote on it, and the number of Atoms they own influences the weight of the vote.
Governance & Membership on Polkadot
The governance and membership on Polkadot have a multicameral governance structure and have several ways to enact legislation. Every proposal must pass by popular vote, and results are decided by a majority of tokens. Polkadot uses adaptive quorum biasing for a referendum with low turnout. The referendum includes proposals like fund distribution from an on-chain treasury. On-chain decisions are autonomous and legally binding, and Polkadot has many on-chain permissionless bodies. The main body is the Council which comprises a set of accounts chosen in a Phragmén-style election. A proposal with universal support from the Council, and representing minority concerns is more likely to pass a public referendum. A Technical Committee exists to provide technical advice (e.g. emergency runtime upgrade to fix a bug).
4. Security Models on Cosmos and Polkadot
Cosmos and Polkadot have different approaches to tackling security. Polkadot uses shared security measures, which entail two parachains with two different levels of security- a uniform security level and a fishing technique to reverse the entire transaction if an incorrect block is found. The validators in Cosmos ensure that malicious activity in a zone does not negatively impact the network.
Cosmos Security model
The Cosmos security model is as follows every blockchain in the Cosmos Network is independent and secures itself instead of employing a local/global architecture for security. Each blockchain operates under its consensus, and only that blockchain’s validators maintain its security. The network’s interoperability is due to the hub-and-zone paradigm, in which zones (separate blockchains) can send tokens to other zones by traveling through a hub (also an independent blockchain). This method of communicating between chains to depict token transfers is known as IBC (Inter-Blockchain Communication). The IBC protocol is a work-in-progress that initially supports token transfers before expanding to include other messages sent between blockchains.
Polkadot Security model
The Polkadot security model uses shared security or pooled security in certain documents, which is one of the distinctive value propositions for chains thinking about joining the Polkadot network as a parachain. Shared security means that the financial security offered by the Relay Chain validators is shared by any parachains connected to the Polkadot Relay Chain by renting a parachain slot.
In bridge protocols, each chain is considered to be independent and upholds its own validator set and financial stability. Another security measure used by Polkadot is using fishermen to reverse the entire transaction if they find an incorrect block. Polkadot uses a cross-consensus message passing style to send random messages to each other (XCM).
5. Blockchain interoperability – Cosmos vs Polkadot
Data accessibility via a variety of networks is known as interoperability. One use case would be to execute avalanche transactions on the Polkadot network using an Ethereum contract. In Cosmos vs. Polkadot, the inter-blockchain communication design is very different. Polkadot makes data and asset transfers between several blockchain networks possible by facilitating communication between two parachains using transfer tokens and other methods.
Cosmos, on the other hand, concentrates on moving resources between chains. The Tendermint consensus, a round-robin technique that enables instant finality, is used by Cosmos (both the Hub and the zones). The algorithm creates and finalizes blocks one at a time since block production and finalization follow the same path. It has quadratic transport complexity because it is a PBFT-based method (like GRANDPA), yet it can only finalize one block at a time.
Cosmos blockchain interoperability
Cosmos blockchain interoperability uses a consensus algorithm that complies with the ABCI spec and can be used by any blockchain on the Cosmos Network. Only the Tendermint algorithm complies with this specification as of right now. Cosmos is working on developing other consensus algorithms to improve interoperability. The Tendermint algorithm creates finality for each block by having each validator communicate with one another to approve or reject each given block. The algorithm has undergone live stress testing with 200 validators and 6-second block durations during Game of Stakes, and it is quick. The Tendermint algorithm is available right out of the box thanks to the software development kit that the Cosmos team offers.
Polkadot blockchain interoperability
Polkadot blockchain interoperability approach can support a number of validators and allows the Relay Chain to quickly finish multiple blocks from all the parachains (over 1000). This can be explained simply by the fact that not all validators are required to vote on every block; instead, validators can vote on the highest block they believe to be legitimate, and the algorithm transitively applies the vote to all of that block’s ancestors. The program then determines the set of blocks with the supermajority vote and treats those as the final set. Polkadot is still developing GRANDPA, and its performance in the actual world is unknown.
6. Scalability and upgrading on Polkadot and Cosmos
If we compare the scalability of Polkadot and Cosmos, we find Polkadot has more robust scalability options. Polkadot can reach 1 million TSP with parachains, while Cosmos can start its network that runs parallel to the main network. On the upgrades features, Polkadot offers upgrades without hard forks, while Cosmos upgrades are possible with hard forks.
Cosmos interoperability ensures the scalable system will function properly. With the help of the Cosmos interoperability model of shared communication standards, any sovereign blockchain can connect and improve the protocol design. Cosmos achieves greater scalability by separating the applications into many application-specific blockchains or replicating a blockchain to reduce congestion. Token transfers between chains let these several chains function as one network. Developers can start their new blockchains and use the SDK to launch a parallel network to the main network.
Parachains reduce the number of transactions that could clog up on Polkadot’s native chain because they are their distinct blockchains processing their transactions. Instead of the vertical scalability present on a network like Ethereum, Polkadot scalability is horizontal. On the Polkadot network, parachains are designed for use in particular scenarios. The majority of the computation on Polkadot can be handled by the parachains because they are inherently scalable. This resolves the scalability problems that other blockchains, like Ethereum, have and some of the centralization problems that blockchains like Binance Smart Chain have (BSC).
7. Staking Mechanics on Cosmos and Polkadot
Comparing the stalking mechanism on Cosmos and Polkadot we see the Cosmos (ATOM) and Polkadot (DOT) tokens have similar functions in their respective ecosystems. Holders can use their stake to influence governance or stake their tokens to validate transactions either alone or alongside other validators. Polkadot validators are chosen using the nominated proof-of-stake g a nominated proof-of-stake (NPoS) procedure, while Cosmos Hub uses bonded proof-of-stake (a variant of delegated PoS) to select validators.
Staking on Cosmos
Staking on Cosmos uses bonded proof-of-stake model. for each validator they wish to delegate to, holders must bond funds and submit a delegate transaction along with the appropriate number of tokens. Up to 300 validators will be supported by the Cosmos Hub.
In Cosmos, both consensus voting and rewards are based on stakes. Instead of 2/3 of the validators, more than 2/3 of the stake must commit in a consensus vote. A validator that contributes 10% of the total stake will also receive 10% of the prizes.
Polkadot Stalking utilizes the Nominated Proof of Stake (NPoS) model to choose validators with the help of the sequential Phragmén algorithm. The governance determines the size of the validator set (1000 validators are intended), and stakeholders who do not wish to manage the infrastructure for validators can propose up to 16 validators. Phragmén’s algorithm helps choose the optimal stake allocation, where optimal refers to having the most evenly staked out. Phragmén’s algorithm chooses the optimal stake allocation, where optimal refers to the most evenly staked set.
Polkadot’s consensus mechanisms give equal weight to all validators. In other words, rather than 2/3 of the stake, more than 2/3 of the validators must back a chain to obtain greater than 2/3 of support. The same is true for validators, who are rewarded based on their activity, principally block production and finality justifications, rather than their stake. Given that they will receive greater returns on their staked tokens, validators who are nominated with lesser stakes will be encouraged to do so.
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