Core Protocol

Binary messages exchanged between Ixian Core peers. Each message has a numeric code and may have a request/response pairing. Detailed structure for each message is documented on its own subpage.

Envelope (v6)

This section defines the binary envelope used by all core messages and links to each message specification. Every message lives in its own file.

Offset	Size	Type	Field	Description
0	1	uint8	start	Constant 0xEA
1	2	uint16	code	ProtocolMessageCode for the payload
3	4	uint32	length	Payload length in bytes (must be > 0, < 50MB)
7	4	uint32	checksum	CRC32C of the payload bytes
11	1	uint8	headerChecksum	XOR checksum over the 11 header bytes above
12	N	byte[length]	payload	Message payload, structure depends on code

Header checksum: computed by XOR'ing all header bytes before headerChecksum, starting with seed 0x7F.

Payload checksum: CRC32C (Castagnoli) over the payload bytes.

Global Serialization Rules

The following rules apply to all message payloads unless specified otherwise.

• Endianness: All multi-byte integer types (uint16, int32, uint64, etc.) are serialized in Little-Endian byte order.
• String Encoding: All strings are encoded using the standard .NET BinaryWriter format, which prefixes the UTF-8 bytes with the string's length encoded as a 7-bit integer.

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Handshake

Name	Code	Description
hello	0	Initiates handshake; includes node ID, network ID, and capabilities.
helloData	1	Response to hello, confirming handshake and sharing peer data.
bye	2	Graceful session termination with details disconnection.

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Presence

Name	Code	Description
getKeepAlives	6	Requests active presence data from peer.
keepAlivesChunk	7	Chunked response containing presence entries.
updatePresence	24	Announces local presence change.
keepAlivePresence	34	Sends or updates a single presence entry.
getPresence2	36	Requests specific presence records.
getRandomPresences	48	Requests a random subset of active presences for seeding/discovery.
getSectorNodes	18	Requests nodes for a sector or region.
sectorNodes	19	Returns sector node list.

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Blocks / Headers

Name	Code	Description
getBlockHeaders3	46	Requests block headers by height range or locator.
blockHeaders3	47	Returns full block headers.
compactBlockHeaders1	50	Returns compact (reduced) block headers for fast sync.
getBlock3	55	Requests full block by hash or height.
blockData2	9	Full block data response (transactions, signatures, metadata).
blockSignature2	13	Announces or relays a block signature.
getBlockSignatures2	14	Requests block signatures for a specific block.
getSignatures3	15	Requests signatures using the latest format.
signaturesChunk2	17	Chunked response containing one or more signatures.
getRelevantBlockTransactions	49	Requests only transactions relevant to a peer for a given block.

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Transactions

Name	Code	Description
getTransactions2	56	Requests multiple transactions by hash list or range.
transactionsChunk3	60	Chunked response containing transaction data.
getTransaction3	58	Requests a single transaction by ID.
transactionData2	8	Provides single transaction data.

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Other

Name	Code	Description
getBalance2	30	Requests wallet balance by address.
balance2	31	Returns wallet balance data.
inventory2	59	Announces available blocks or transactions by hash or height.
rejected	3	Message rejected with details about rejection.
s2data	26	Transfers S2 data payloads across the overlay.

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Notes

• Messages with Chunk may repeat until the dataset is complete.
• Numeric codes are for wire-level interoperability; use symbolic names in code.
• Obsolete and deprecated codes are intentionally omitted here.