Blockchain Interoperability


  1. Application/Smart Contracts on different chains can interact with each other (cross-chain contract calls)

  2. Cosmos Hub allows for deep integration of token economies

  3. Token transfers, not just basic token swaps

  4. Private-public interoperability


  • Think of it like WWW - The internet of blockchain

  • connecting many blockchains to help with scaling

  • SOVEREIGNTY - private chains can interoperate with public chains

How to convert ETH to BTC?
  1. A trusted intermediary zone will be created for Ethereum and there will be set of validators who will be responsible for relaying messages from the Ethereum bridge-zone to the Cosmos Hub.

  2. Since both Ethereum and Bitcoin are probabilistic (there is a chance the current chain isn’t the correct one), the validators need to wait for a certain number of confirmations to ensure the transaction actually went through.

  3. Once the validators are certain the transaction is final they’ll initiate a transaction from their zone to the Cosmos Hub that they did indeed receive the Ether. The hub will then create a form of Wrapped Cosmos Ether that it’ll hold. Every other Cosmos zone will now be aware there’s new Wrapped Cosmos Ether in the system.

  4. Assuming an exchange rate was determined beforehand, the Wrapped Cosmos Ether will be exchanged for Wrapped Cosmos Bitcoin. This Wrapped Cosmos Bitcoin is then sent to the trusted intermediary Bitcoin zone and sent to the specified address on the actual Bitcoin chain.

Cosmos Hub

  • Think of it as ISP

  • Built with Cosmos SDK

  • Acts as a routing mechanism, which allows chains to talk to each other

  • Also allows deep integration of token economies

  • Prevents chains from double spending other chains

Macro view of the Cosmos Network, Cosmos Hub, and Tendermint


  • Think of it like OS

  • Consensus algorithm (inspired by PBFT) created by Jae Kwon in 2014

  • Since no confirmations are required this is called having “fast finality”

Inter-Blockchain Communication (IBC)

  • Think of it like TCP/IP

  • Basically a side chain

  • a 2-way on-chain light client protocol

  • Allows any chains that are using tendermint to talk to each other and share information amongst each other (token, data etc.)


  • SOVEREIGNTY - Polkadot wants you to give up your chain's sovereignty and want you to use their validators

  1. Each parachain gain pooled security from the validator set of the relay chain. Once a chain has connected to the Polkadot network by becoming a parachain it is secured with the same level of security as the whole Polkadot network. In Cosmos, each new chain needs its own validator set and has to bootstrap its own security.

  2. Parachains can interact with other parachains using trust-fee interchain communication. Users who want to communicate across chains do not need to trust every chain they transmit messages to, but just the singular security of the whole Polkadot network. Again, this is different from how Cosmos works where a user would need to trust the source chain, the routing chains, and the destination chain with each of their separate validator sets.

In the Polkadot ecosystem:

  • Collators — Produce the blocks for parachains and pass the information to the validators to verify.

  • Nominator — Allocates their capital to validators to participate in the staking mechanism.

  • Validator — Require a high bond requirement because they are responsible for actually sealing the new blocks of the relay chain. Their crucial roles include:

  • Authoring new blocks.

  • Finalizing the relay chain through participation in GRANDPA.

  • Validating parachain blocks by ensuring the transactions which occurred are correct and that the cross-chain messages have been processed.

  • Fishermen — Bounty hunters who “go fishing” for malicious actors by watching the other nodes of the network.