getRelevantBlockTransactions (49)

The getRelevantBlockTransactions message is a specialized request designed for light clients. It allows a client to download only the transactions that are relevant to its own wallet addresses, significantly reducing bandwidth and storage requirements.

Relevance is determined by a Cuckoo Filter, a compact, probabilistic data structure that contains a representation of the client's wallet addresses.

Core Data Types

• IxiVarUInt: See IxiVarInt Encoding.
• IxiBytes: See IxiBytes Encoding.

Payload Structure

Field	Data Type	Min	Max	Description
fromBlockNum	IxiVarUInt	1		The block number from which to start searching.
count	IxiVarUInt	1		The number of consecutive blocks to search through.
cuckooFilter	IxiBytes			A serialized Cuckoo Filter containing the wallet addresses the client is interested in.

Behavioral Notes

• This is the primary synchronization message for light clients that do not need the entire blockchain history.
• Upon receiving this message, a full node must iterate through the blocks in the requested range (fromBlockNum to fromBlockNum + count).
• For each transaction in each block, the node must check if any of the transaction's output addresses (toAddress) are likely contained within the provided cuckooFilter.
• All matching transactions are then sent back to the requester in one or more transactionsChunk3 messages.