Existing interoperability systems can be differentiated by determining who assumes the responsibility of mirroring information across blockchains.
The following pverview categorizes existing interoperability systems by the chosen approach for verifying crosschain data:
Cheap/fast, easy to build, & extend
Chain's own validator set verifies xchain data. Typically done by running a light client of origin chain inside of the destination chain's VM
IBC, Near Rainbowbridge, BTC Relay, rollup entry/exit
3rd party validator set verifies data across chains. AKA PoS/MPC systems
Thorchain, Anyswap, Synapse, Hyphen, etc.
N-party system is reduced to 1:1 interaction, very easy to keep trust-minimized
Connext, Hop, simple atomic swaps