Glossary
IBC Light Client
The on-chain verifier that lets a Cosmos chain trust messages from another chain — verifies the source chain's block headers against its own consensus rules.
IBC's security model relies on light clients. Each chain runs an on-chain light client of every chain it connects to. When a counterparty sends a packet (asset transfer, message), the receiving chain's light client verifies that the packet was included in a finalized block on the source chain by checking the source's consensus signatures.
The result is "trust-minimized" interop — the security of the connection reduces to the honesty of each chain's own consensus, with no shared multisig or external committee. CometBFT, Solana, and Ethereum (via 02-client) all have IBC light-client implementations.