Glossary
This glossary defines and explains many LayerZero concepts and terminology.
User Application (UA)
A User Application (UA) is any contract that uses LayerZero to send & receive messages between blockchains. We define UA as a tuple (chainId, contractAddress)
-
the UA that
send()
the message at the source chain assrcUA
(srcChain, srcAddress)
-
the UA that
lzReceive()
at the destination chain asdstUA
(dstChain, dstAddress)
In LayerZero's perspective, srcUA
and dstUA
are different, though they might be the same entity.
Ultra-Light Node (ULN)
ULN is a messaging protocol, firstly introduced in the LayerZero white paper, that allows lightweight cross-chain messaging with configurable trustlessness on the specification of Oracle and Relayer, the two roles that are relaying block information and transaction proof across chains.
Oracle
A contract address that can be notified to move a block header.
What is a Relayer?
Any process that delivers a transaction proof in the LayerZero system.
Messaging Library
The contract that handles the message payload packing on the source chain and verification on the destination chain. Ultra-Light Node is an implementation of Messaging Library
Proof Library
The contract that verifies the validity of a proof. Merkle Patricia Tree inclusion proof is an implementation of Proof Library.