Key concepts

This page defines the concepts referenced across operator, wallet, and builder docs.

Cycle, block, LSU

• Cycle: the consensus time unit.
• Block: the explorer-friendly term for a cycle that produced a ledger update.
• LSU (Ledger State Update): the applied state transition for a cycle.

Important: some cycles legitimately produce no LSU, so catalyst_getBlockByNumber(<cycle>) can return null.

Accounts, keys, identifiers

• Protocol account: identified by a 32-byte public key (pubkey32), hex-encoded as 0x<64 hex>.
• EVM address: 20-byte hex address (address20), 0x<40 hex>.

In several places, Catalyst derives the EVM address from a protocol key:

• evm_sender = last20(pubkey32)

Canonical reference: catalyst-sdk/README.md (“Deterministic contract addresses”).

Transactions (CTX2)

Catalyst tooling uses CTX2 transactions submitted via:

• catalyst_sendRawTransaction

This is not Ethereum eth_sendRawTransaction.

Canonical references:

• catalyst-sdk/README.md (CTX2 + method name)
• catalyst-node-rust/crates/catalyst-rpc/src/lib.rs (catalyst_sendRawTransaction)

Typical transaction flow

• Fetch signing domain: catalyst_getTxDomain
• Build + sign tx (SDK or CLI)
• Submit: catalyst_sendRawTransaction
• Poll: catalyst_getTransactionReceipt
• For contracts, verify code: catalyst_getCode

See RPC: transaction lifecycle for end-to-end examples.