Blockchain Transmission Protocol (BTP) is ICON’s interoperability solution.

What is BTP?

BTP (Blockchain Transmission Protocol) is a protocol standard that renders heterogeneous blockchains interoperable, including blockchains that entail completely different consensus models and algorithms.

Interoperability is the ability to facilitate value transfer, service invocation, and data exchange. These siloed operating blockchains can securely anchor transactions through a universal standard as a trust-less settlement layer.


How BTP works?

This is an amazing thread on Twitter by @real_digidavid will give you a digestible recap to an interview by Scott Smiley & Micheal Rosmer where the workings of BTP is discussed in detail.

For a more in-depth answer here is a brilliant medium article on BTP by @Iconographer

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Go on admit it, you would like to hear about BTP next time you’re jogging or cycling here is a brilliant community session on Eye on Icon – Community Session on BTP.

Podcast on BTP

Key Differences?

BTP is unique amongst existing interoperability solutions. Most solutions require some sort of game theory, slashing/penalties for validators, PBFT consensus, critical off-chain components or centralization.

The Verifier contract is the key differentiator of BTP. As mentioned earlier, other interoperability solutions rely on trusting the Relays or some sort of game theory, but BTP is secured entirely through cryptography. BTP is as secure with 1 Relay as it would be with 100 Relays. Extra Relays simply ensure more reliability and liveliness.

Additionally, BTP’s out-of-the-box infrastructure combined with a generalized architecture opens the door for simple integration by any 3rd party developer exploring unique use cases. Individual 3rd party developers do not need their own Relay networks, as the ICON Network provides that infrastructure and covers the costs. Developers simply need to build their own Service Contract (generalized architecture) to meet their needs, submit a Pull Request to get their Service Contract approved, then it will be serviced by ICON’s Relay Network and secured by BTP smart contracts.

And lastly, any network added to the BTP ecosystem becomes directly connected to all other networks in the ecosystem. There is no need to build bridges between all networks. Through inclusion in the BTP ecosystem, all chains are directly connected with one another.

Interoperability Comparison Table

Rather than going through all Interoperability solutions individually, I would like to illustrate via a comparison table how Icons BTP is different by using a set of parameters (see Table 1).

  1. Purpose;
  2. Interoperability

    There are roughly four types of bridges to enable Interoperability, each with its own benefits and drawbacks;
    • Asset specific
      A bridge with the sole purpose of providing access to a specific asset from a foreign chain. 
    • Chain specific
      A bridge between two blockchains which usually supports simple operations around locking & unlocking tokens on the source chain and minting any wrapped asset on the destination chain.
    • Application specific
       An application that provides access to two or more blockchains, but solely for use within that application.
    • Generalised
       A protocol specifically designed for transferring information across multiple blockchains. 
  3. Layer of communication;
  4. Connection Method;
  5. Connection Speed;
  6. Scalability;
  7. Fault tolerance;
  8. Security;

    For Interoperability you could roughly categorise security as:
    • Trust-Less
      The bridge’s security is equal to that of the underlying blockchain(s) it is bridging.
    • Trusted
      Actors do not post collateral and users do not recover funds in case of system failure or malicious activity, so users are mainly relying on the reputation of the bridge operator.
    • Insured
      Malicious actors are able to steal user funds, but it is likely unprofitable for them to do so because they are required to post collateral and get slashed in the case of error or misbehaviour. If user funds are lost, they will be reimbursed through slashed collateral. Risk would increase if funds are greater than collateral.
table interoperability
Table 1

“One of the things that I get most excited by is the security aspect of it. So, the way most of these interoperability solutions work currently is some sort of Proof of Authority node system amongst the relays where there needs to be come consensus among relays. Whether its 2/3+ consensus or a multi-signature wallet, in the end the relays themselves control the minting and burning and locking and unlocking of assets that are being transferred, while in ICON’s BTP, the relays have absolutely no control over any of the smart contracts. They cannot be malicious, even if they colluded. All they can do is fail to deliver messages. On ICON, relays are a source of liveness, whereas on most other interoperability solutions, relays are a source of security and a source of risk

Scott Smiley, Director of Strategy for the ICON Project.

For a more thorough walkthrough of the differences between BTP, Polkadot, Cosmos, Wormhole, and more, I would highly recommend reading Iconographer’s BTP guide & Brian Li What ICON 2.0 Means for the ICON Ecosystem.

This webpage is a collection of information from the community for the community.