Cross-chain Verification - c8ntinuum Docs

Cross-chain verification precompiles let contracts reason about state or messages from other systems without trusting a bridge committee. They are for applications that need proof-carrying cross-chain behavior, not just ordinary local contract calls.

Surfaces

Surface	Address	Use it for	Status in docs
ICS02 client	`0x0000000000000000000000000000000000000807`	Client updates, membership proofs, and non-membership proofs.	ABI reference available
ICS20 transfer	`0x0000000000000000000000000000000000000802`	IBC fungible token transfer flows.	Learn page and ABI reference available
SP1 Groth16 verifier	`0x0000000000000000000000000000000000000600`	Verifying Groth16 proofs from SP1 programs.	ABI and gas schedule available
SP1 Plonk verifier	`0x0000000000000000000000000000000000000700`	Verifying Plonk proofs from SP1 programs.	ABI and gas schedule available

When to use

Use ICS02 when a contract needs to verify a statement about remote chain state.
Use ICS20 when the application flow is token movement over IBC.
Use SP1 verifiers when the expensive computation or state transition is proven off-chain and checked on-chain.

Design notes

Concern	Guidance
Trust model	Safety should reduce to source-chain consensus, proof soundness, and light-client verification.
Liveness	Relayers or off-chain provers may affect completion time even when verification is trust-minimized.
Timeouts	Cross-chain flows need explicit timeout and acknowledgement handling.
Gas	Proof verification can be large; use Precompile ABI Reference for formulas.