Canisters are smart contracts unique to ICP.

The name possibly implies self-contained decentralised applications that can be a website, a SaaS, or a dAO.

List of terms and abbreviations

  • Tx (transactions)
  • Canisters
  • Smart contracts


Canister smart contracts have many ECDSA keys

This is what was described in the ICP Fusion Educate. There are so much complexity here that the video is best to watch

since these are just notes anyway to at least to let me write my own summary of what I understand.

Chain Key Cryptography

Communication between protocols and even between smart contracts use Chain Key Cryptography. I have heard of this before when using multiple PGP keys but never dived much into it. I believe based on the name, it is a chain of public keys created between recipients and senders before reaching the final destination. I won’t assume I know this because I am no cryptographer.

However, ICP believes that this cryptographic primitive is powerful.


HTTPS Outcalls

Smart contracts communicate well with Web3 primitives specifically in a decentralised network. However, there is still a need to communication to Web 2.0.

ICP allows HTTPS Outcalls to communicate between Web 2.0 applications or services off-chain.

Subnets send an HTTP request to an HTTP server. If all of the nodes in the subnet either fail or are slightly delayed, transformation functions or filter functions either transform or filter the result. This is to filter out errors and or transform data to determine the timestamps. Once a supermajority of the results are the same, the answer is delivered to the canister smart contract.