Data Messages#

The following network messages all request or provide data related to transactions and blocks.

Overview Of P2P Protocol Data Request And Reply Messages

Many of the data messages use inventories as unique identifiers for transactions and blocks. Inventories have a simple 36-byte structure:

Bytes

Name

Data Type

Description

4

type identifier

uint32_t

The type of object which was hashed. See list of type identifiers below.

32

hash

char[32]

SHA256(SHA256()) hash of the object in internal byte order.

The currently-available type identifiers are:

Type Identifier

Name

Description

1

MSG_TX

The hash is a TXID.

2

MSG_BLOCK

The hash is of a block header.

3

MSG_FILTERED_BLOCK

The hash is of a block header; identical to MSG_BLOCK. When used in a getdata message, this indicates the response should be a merkleblock message rather than a block message (but this only works if a bloom filter was previously configured). Only for use in getdata messages.

6

MSG_SPORK

The hash is Spork ID.

16

MSG_DSTX

The hash is CoinJoin Broadcast TX.

17

MSG_GOVERNANCE_OBJECT

The hash is a Governance Object.

18

MSG_GOVERNANCE_OBJECT_VOTE

The hash is a Governance Object Vote.

20

MSG_CMPCT_BLOCK

The hash is of a block header; identical to MSG_BLOCK. When used in a getdata message, this indicates the response should be a cmpctblock message. Only for use in getdata messages.

21

MSG_QUORUM_FINAL_COMMITMENT

The hash is a long-living masternode quorum final commitment.
Added in 0.13.0

23

MSG_QUORUM_CONTRIB

The hash is a long-living masternode quorum contribution.
Added in 0.14.0

24

MSG_QUORUM_COMPLAINT

The hash is a long-living masternode quorum complaint.
Added in 0.14.0

25

MSG_QUORUM_JUSTIFICATION

The hash is a long-living masternode quorum justification.
Added in 0.14.0

26

MSG_QUORUM_PREMATURE_COMMITMENT

The hash is a long-living masternode quorum premature commitment.
Added in 0.14.0

28

MSG_QUORUM_RECOVERED_SIG

The hash is a long-living masternode quorum recovered signature.

Note: Only relayed to other masternodes in the same quorum and nodes that have sent a qwatch message as of Dash Core 0.17.0
Added in 0.14.0

29

MSG_CLSIG

The hash is a ChainLock signature.
Added in 0.14.0

31

MSG_ISDLOCK

The hash is an LLMQ-based deterministic InstantSend lock (DIP22).
Added in 18.0

Deprecated Type Identifiers

The following type identifiers have been deprecated recently. To see type identifiers removed longer ago, please see the previous version of documentation.

Type Identifier

Name

Description

4

MSG_LEGACY_TXLOCK_REQUEST

Deprecated in 20.0.0
MSG_TXLOCK_REQUEST prior to Dash Core 0.15.0. The hash is an InstantSend transaction lock request. Transactions received this way are automatically converted to a standard tx message as of Dash Core 0.15.0.

5

MSG_TXLOCK_VOTE

Deprecated in 0.15.0
The hash is an InstantSend transaction vote.

30

MSG_ISLOCK

Deprecated in 20.1.0
The hash is an LLMQ-based InstantSend lock (DIP10).
Added in 0.14.0

Type identifier zero and type identifiers greater than those shown in the table above are reserved for future implementations. Dash Core ignores all inventories with one of these unknown types.

block#

The block message transmits a single serialized block in the format described in the serialized blocks section. See that section for an example hexdump. It can be sent for two different reasons:

  1. GetData Response: Nodes will always send it in response to a getdata message that requests the block with an inventory type of MSG_BLOCK (provided the node has that block available for relay).

  2. Unsolicited: Some miners will send unsolicited block messages broadcasting their newly-mined blocks to all of their peers. Many mining pools do the same thing, although some may be misconfigured to send the block from multiple nodes, possibly sending the same block to some peers more than once.

blocktxn#

Added in protocol version 70209 of Dash Core as described by BIP152

The blocktxn message sends requested block transactions to a node which previously requested them with a getblocktxn message. It is defined as a message containing a serialized BlockTransactions message.

Upon receipt of a properly-formatted requested blocktxn message, nodes should:

  1. Attempt to reconstruct the full block by taking the prefilledtxn transactions from the original cmpctblock message and placing them in the marked positions

  2. For each short transaction ID from the original cmpctblock message, in order, find the corresponding transaction (from either the blocktxn message or from other sources)

  3. Place each short transaction ID in the first available position in the block

  4. Once the block has been reconstructed, it shall be processed as normal.

Short transaction IDs are expected to occasionally collide. Nodes must not be penalized for such collisions.

The structure of BlockTransactions is defined below.

Bytes

Name

Data Type

Encoding

Description

32

blockhash

Binary blob

The output from a double-SHA256 of the block header, as used elsewhere

The blockhash of the block which the transactions being provided are in

1 or 3

transactions
_length

CompactSize

As used to encode array lengths elsewhere

The number of transactions provided

Varies

transactions

List of transactions

As encoded in tx messages in response to getdata MSG_TX

The transactions provided

The following annotated hexdump shows a blocktxn message. (The message header has been omitted.)

182327cb727da7d60541da793831fd0ab0509e79c8cd
3d654cdf3a0100000000 ....................... Block Hash

01 ......................................... Transactions Provided: 1

Transaction(s)
| Transaction 1
| | 01000000 ................................ Transaction Version: 1
| | 01 ...................................... Input count: 1
| |
| | Transaction input #1
| | |
| | | 0952617a516d956e2ecee71a6adc249f
| | | 4bb757adcc409452ab98c8e55c31e62a ..... Outpoint TXID
| | | 00000000 ............................. Outpoint index number: 0
| | |
| | | 6b ................................... Bytes in sig. script: 107
| | | 483045022100d10edf447252e1e69ff1
| | | 77330bb2c889a50be02e00cc5d79c0d0
| | | 79ae56518fc40220245d36905dc950fc
| | | d55694cfde8cde3109dc80b12aca3a6e
| | | 332033802ee36e1b01210272cc6e7660
| | | 2648831d8e80fca8eb24369cd0f23ff0
| | | 79cf20ae9d9beee05de6db ............... Secp256k1 signature
| | |
| | | ffffffff ............................. Sequence number: UINT32_MAX
| |
| | 02 ..................................... Number of outputs: 02
| |
| | Transaction output #1
| | | 0be0f50500000000 ..................... Duffs (0.99999755 Dash)
| | |
| | | 19 ................................... Bytes in pubkey script: 25
| | | | 76 ................................. OP_DUP
| | | | a9 ................................. OP_HASH160
| | | | 14 ................................. Push 20 bytes as data
| | | | | 923d91ed359f650eec6ea8b9030b340d
| | | | | ea63d590 ......................... PubKey hash
| | | | 88 ................................. OP_EQUALVERIFY
| | | | ac ................................. OP_CHECKSIG
| |
| | [...] .................................. 1 more tx output omitted
| |
| | 00000000 ............................... locktime: 0 (a block height)

cfcheckpt#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The cfcheckpt message is sent in response to the getcfcheckpt message. The filter headers included are the set of all filter headers on the requested chain where the height is a positive multiple of 1,000.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested. Should match the field in the getcfcheckpt message being responded to.

32

stop_hash

uint256

The hash of the last block in the requested range. Should match the field in the getcfcheckpt message being responded to.

1-3

filter_headers
_length

CompactSize

The length of the following vector of filter headers

filter_headers
_length * 32

filter_hashes

[][32]byte

The filter headers at intervals of 1,000

cfheaders#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The cfheaders message is sent in response to the getcfheaders message. Instead of including the filter headers themselves, the response includes one filter header and a sequence of filter hashes, from which the headers can be derived. This has the benefit that the client can verify the binding links between the headers.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested. Should match the field in the getcfheaders message being responded to.

32

stop_hash

uint256

The hash of the last block in the requested range. Should match the field in the getcfheaders message being responded to.

32

previous_filter
_header

uint256

The filter header preceding the first block in the requested range

1-3

filter_hashes
_length

CompactSize

The length of the following vector of filter hashes. Must not be > 2000.

filter_hashes
_length * 32

filter_hashes

[][32]byte

The filter hashes for each block in the requested range

cfilter#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The cfilter message is sent in response to the getcfilters message, one for each block in the requested range.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested. Should match the field in the getcfilters message being responded to.

32

block_hash

uint256

Block hash of the block for which the filter is being returned. Must correspond to a block that is an ancestor of the request’s stop_hash with a height >= start_height.

1-5

num_filter_bytes

CompactSize

A variable length integer representing the size of the filter in the following field

num_filter_bytes

filter_bytes

[]bytes

The serialized compact filter for this block

cmpctblock#

Added in protocol version 70209 of Dash Core as described by BIP152

The cmpctblock message is a reply to a getdata message which requested a block using the inventory type MSG_CMPCT_BLOCK. If the requested block was recently announced and is close to the tip of the best chain of the receiver and after having sent the requesting peer a sendcmpct message, nodes respond with a cmpctblock message containing data for the block.

If the requested block is too old, the node responds with a full non-compact block

Upon receipt of a cmpctblock message, after sending a sendcmpct message, nodes should calculate the short transaction ID for each unconfirmed transaction they have available (i.e. in their mempool) and compare each to each short transaction ID in the cmpctblock message. After finding already-available transactions, nodes which do not have all transactions available to reconstruct the full block should request the missing transactions using a getblocktxn message.

A node must not send a cmpctblock message unless they are able to respond to a getblocktxn message which requests every transaction in the block. A node must not send a cmpctblock message without having validated that the header properly commits to each transaction in the block, and properly builds on top of the existing, fully-validated chain with a valid proof-of-work either as a part of the current most-work valid chain, or building directly on top of it. A node may send a cmpctblock message before validating that each transaction in the block validly spends existing UTXO set entries.

The cmpctblock message contains a vector of PrefilledTransaction whose structure is defined below. A PrefilledTransaction is used in HeaderAndShortIDs to provide a list of a few transactions explicitly.

Bytes

Name

Data Type

Encoding

Description

1 or 3

index

CompactSize

Compact Size, differentially encoded since the last PrefilledTransaction in a list

The index into the block at which this transaction is

Varies

tx

Transaction

As encoded in tx messages sent in response to getdata MSG_TX

Transaction which is in the block at index index

The cmpctblock message is compromised of a serialized HeaderAndShortIDs structure which is defined below. A HeaderAndShortIDs structure is used to relay a block header, the short transactions IDs used for matching already-available transactions, and a select few transactions which we expect a peer may be missing.

Bytes

Name

Data Type

Encoding

Description

80

header

Block header

First 80 bytes of the block as defined by the encoding used by block messages

The header of the block being provided

8

nonce

uint64_t

Little Endian

A nonce for use in short transaction ID calculations

1 or 3

shortids_
length

CompactSize

As used to encode array lengths elsewhere

The number of short transaction IDs in shortids (i.e. block tx count - prefilledtxn
_length)

Varies

shortids

List of 6-byte integers

Little Endian

The short transaction IDs calculated from the transactions which were not provided explicitly in prefilledtxn

1 or 3

prefilledtxn
_length

CompactSize

As used to encode array lengths elsewhere

The number of prefilled transactions in prefilledtxn (i.e. block tx count - shortids
_length)

Varies

prefilledtxn

List of Prefilled
Transactions

As defined by Prefilled
Transaction definition below

Used to provide the coinbase transaction and a select few which we expect a peer may be missing

Short Transaction ID calculation#

Short transaction IDs are used to represent a transaction without sending a full 256-bit hash. They are calculated as follows,

  • A single-SHA256 hashing the block header with the nonce appended (in little-endian)

  • Running SipHash-2-4 with the input being the transaction ID and the keys (k0/k1) set to the first two little-endian 64-bit integers from the above hash, respectively.

  • Dropping the 2 most significant bytes from the SipHash output to make it 6 bytes.

The following annotated hexdump shows a cmpctblock message. (The message header has been omitted.)

00000020981178a4342cec6316296b2ad84c9b7cdf9f
2688e5d0fe1a0003cd0000000000f64870f52a3d0125
1336c9464961216732b25fbf288a51f25a0e81bffb20
e9600194d85a64a50d1cc02b0181 ................ Block Header

3151b67e5b418b9d ............................ Nonce

01 .......................................... Short IDs Length: 1
483edcd3c799 ................................ Short IDs

01 .......................................... Prefilled Transaction Length: 1

Prefilled Transactions
| 00 ........................................ Index: 0
|
| Transaction 1 (Coinbase)
| | 01000000 ................................ Transaction Version: 1
| | 01 ...................................... Input count: 1
| |
| | Transaction input #1
| | |
| | | 00000000000000000000000000000000
| | | 00000000000000000000000000000000 ..... Outpoint TXID
| | | ffffffff ............................. Outpoint index number: UINT32_MAX
| | |
| | | 13 ................................... Bytes in sig. script: 19
| | | 03daaf010e2f5032506f6f6c2d74444153482f Secp256k1 signature
| | |
| | | ffffffff ............................. Sequence number: UINT32_MAX
| |
| | 04 ..................................... Number of outputs: 04
| |
| | Transaction output #1
| | | ffe5654200000000 ..................... Duffs (11.13974271 Dash)
| | |
| | | 19 ................................... Bytes in pubkey script: 25
| | | | 76 ................................. OP_DUP
| | | | a9 ................................. OP_HASH160
| | | | 14 ................................. Push 20 bytes as data
| | | | | b885cb21ad12e593c1a46d814df47ccb
| | | | | 450a7d84 ......................... PubKey hash
| | | | 88 ................................. OP_EQUALVERIFY
| | | | ac ................................. OP_CHECKSIG
| |
| | [...] .................................. 3 more tx outputs omitted
| |
| | 00000000 ............................... locktime: 0 (a block height)

getblocks#

The getblocks message requests an inv message that provides block header hashes starting from a particular point in the block chain. It allows a peer which has been disconnected or started for the first time to get the data it needs to request the blocks it hasn’t seen.

Peers which have been disconnected may have stale blocks in their locally-stored block chain, so the getblocks message allows the requesting peer to provide the receiving peer with multiple header hashes at heights on their local chain. This allows the receiving peer to find, within that list, the last header hash they had in common and reply with all subsequent header hashes.

Note: the receiving peer itself may respond with an inv message containing header hashes of stale blocks. It is up to the requesting peer to poll all of its peers to find the best block chain.

If the receiving peer does not find a common header hash within the list, it will assume the last common block was the genesis block (block zero), so it will reply with in inv message containing header hashes starting with block one (the first block after the genesis block).

Bytes

Name

Data Type

Description

4

version

uint32_t

The protocol version number; the same as sent in the version message.

Varies

hash count

compactSize uint

The number of header hashes provided not including the stop hash. There is no limit except that the byte size of the entire message must be below the MAX_SIZE limit; typically from 1 to 200 hashes are sent.

Varies

block header hashes

char[32]

One or more block header hashes (32 bytes each) in internal byte order. Hashes should be provided in reverse order of block height, so highest-height hashes are listed first and lowest-height hashes are listed last.

32

stop hash

char[32]

The header hash of the last header hash being requested; set to all zeroes to request an inv message with all subsequent header hashes (a maximum of 500 will be sent as a reply to this message; if you need more than 500, you will need to send another getblocks message with a higher-height header hash as the first entry in block header hash field).

The following annotated hexdump shows a getblocks message. (The message header has been omitted.)

71110100 ........................... Protocol version: 70001
02 ................................. Hash count: 2

d39f608a7775b537729884d4e6633bb2
105e55a16a14d31b0000000000000000 ... Hash #1

5c3e6403d40837110a2e8afb602b1c01
714bda7ce23bea0a0000000000000000 ... Hash #2

00000000000000000000000000000000
00000000000000000000000000000000 ... Stop hash

getblocktxn#

Added in protocol version 70209 of Dash Core as described by BIP152

The getblocktxn message requests a blocktxn message for any transactions that it has not seen after a compact block is received. It is defined as a message containing a serialized BlockTransactionsRequest message. Upon receipt of a properly-formatted getblocktxn message, nodes which recently provided the sender of such a message with a cmpctblock message for the block hash identified in this message must respond with either an appropriate blocktxn message, or a full block message.

A blocktxn message response must contain exactly and only each transaction which is present in the appropriate block at the index specified in the getblocktxn message indexes list, in the order requested.

The structure of BlockTransactionsRequest is defined below.

| Bytes | Name | Data Type | Description| |———-|—————–|———————-|———-|——| | 32 | blockhash | Binary blob | The output from a double-SHA256 of the block header, as used elsewhere | The blockhash of the block which the transactions being requested are in | Varies | indexes_length | CompactSize uint | As used to encode array lengths elsewhere | The number of transactions requested | Varies | indexes | CompactSize uint[] | Differentially encoded | Vector of compactSize containing the indexes of the transactions being requested in the block.

The following annotated hexdump shows a getblocktxn message. (The message header has been omitted.)

182327cb727da7d60541da793831fd0a
b0509e79c8cd3d654cdf3a0100000000 ... Block Hash

01 ................................. Index length: 1
01 ................................. Index: 1

getcfcheckpt#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The getcfcheckpt message requests verifiable filter headers for a range of blocks. The response to this message is a cfcheckpt message.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested

32

stop_hash

uint256

The hash of the last block in the requested range

getcfheaders#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The getcfheaders message requests verifiable filter headers for a range of blocks. The response to this message is a cfheaders message.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested

4

start_height

uint32_t

The height of the first block in the requested range

32

stop_hash

uint256

The hash of the last block in the requested range. Must be >= start_height and the difference between them must be less than 2000.

getcfilters#

Added in protocol version 70223 of Dash Core as described by BIP 157.

The getcfilters message requests compact filters of a particular type for a particular range of blocks. The response to this message is a cfilter message.

Bytes

Name

Data Type

Description

1

filter_type

uint8_t

Filter type for which headers are requested

4

start_height

uint32_t

The height of the first block in the requested range

32

stop_hash

uint256

The hash of the last block in the requested range

getdata#

The getdata message requests one or more data objects from another node. The objects are requested by an inventory, which the requesting node typically previously received by way of an inv message.

The response to a getdata message can be a tx message, block message, merkleblock message, dstx message, govobj message, govobjvote message, notfound message, cmpctblock message, or any other messages that are exchanged by way of inv messages.

This message cannot be used to request arbitrary data, such as historic transactions no longer in the memory pool or relay set. Full nodes may not even be able to provide older blocks if they’ve pruned old transactions from their block database. For this reason, the getdata message should usually only be used to request data from a node which previously advertised it had that data by sending an inv message.

The format and maximum size limitations of the getdata message are identical to the inv message; only the message header differs.

getheaders#

Added in protocol version 70077.

The getheaders message requests a headers message that provides block headers starting from a particular point in the block chain. It allows a peer which has been disconnected or started for the first time to get the headers it hasn’t seen yet.

The getheaders message is nearly identical to the getblocks message, with one minor difference: the inv reply to the getblocks message will include no more than 500 block header hashes; the headers reply to the getheaders message will include as many as 2,000 block headers.

Bytes

Name

Data Type

Description

4

version

uint32_t

The protocol version number; the same as sent in the version message.

Varies

hash count

compactSize uint

The number of header hashes provided not including the stop hash.

Varies

block header hashes

char[32]

One or more block header hashes (32 bytes each) in internal byte order. Hashes should be provided in reverse order of block height, so highest-height hashes are listed first and lowest-height hashes are listed last.

32

stop hash

char[32]

The header hash of the last header hash being requested; set to all zeroes to request as many blocks as possible (2000).

getheaders2#

Added in protocol version 70223 of Dash Core.

The getheaders2 message requests a headers2 message that provides block headers starting from a particular point in the block chain. It allows a peer which has been disconnected or started for the first time to get the headers it hasn’t seen yet.

The getheaders2 message contains the same fields as the getheaders message.

getmnlistd#

Added in protocol version 70213

The getmnlistd message requests a mnlistdiff message that provides either:

  1. A full masternode list (if baseBlockHash is all-zero)

  2. An update to a previously requested masternode list

Bytes

Name

Data type

Required

Description

32

baseBlockHash

uint256

Required

Hash of a block the requester already has a valid masternode list of.
Note: Can be all-zero to indicate that a full masternode list is requested.

32

blockHash

uint256

Required

Hash of the block for which the masternode list diff is requested

The following annotated hexdump shows a getmnlistd message. (The message header has been omitted.)

000001ee5108348a2c59396da29dc576
9b2a9bb303d7577aee9cd95136c49b9b ........... Base block hash

0000030f51f12e7069a7aa5f1bc9085d
db3fe368976296fd3b6d73fdaf898cc0 ........... Block hash

getqrinfo#

Added in protocol version 70222 of Dash Core.

The getqrinfo message requests a qrinfo message that provides the information required to verify quorum details for quorums formed using the quorum rotation process.

Bytes

Name

Data type

Required

Description

4

baseBlockHashesNb

uint32

Required

Number of masternode lists the light client already knows (up to 4)

Varies

baseBlockHashes

uint256[]

Required

Array of base block hashes for the masternode lists the light client already knows

32

blockRequestHash

uint256

Required

Hash of the block for which the masternode list diff is requested

1

extraShare

bool

Optional

Flag to indicate if an extra share is requested

The following annotated hexdump shows a getqrinfo message. (The message header has been omitted.)

05 ................................. Number of base block hashes: 5


cb6f9b4f2145f2e3fcf270737ad34d7e
51cdb9e98f2580927c52b35f62010000 ... Base block hash 1
8cfa868eb5adfdfb6ae333b790980f2d
0737c64ccd716ce6b63969f481010000 ... Base block hash 2
41e452b5187bc71a1e92c42c8e38f04b
8c83b12415f7a73b292f5c79c9000000 ... Base block hash 3
0387850f96fb9888bb445cce15b56603
019df551c246e237ff3a6107e8020000 ... Base block hash 4
7ab87c8f16f60fdba20102d348a0af08
2a6590759c6535aa48941e807e020000 ... Base block hash 5

d7b9d67da4a3016c62fcc37157032126
46d11c2b3c533ccf9bb56f7540000000 ... Block request hash

00 ................................. Extra share: false

headers#

Added in protocol version 31800 (of Bitcoin).

The headers message sends block headers to a node which previously requested certain headers with a getheaders message. A headers message can be empty.

Bytes

Name

Data Type

Description

Varies

count

compactSize uint

Number of block headers up to a maximum of 2,000. Note: headers-first sync assumes the sending node will send the maximum number of headers whenever possible.

Varies

headers

block_header

Block headers: each 80-byte block header is in the format described in the block headers section with an additional 0x00 suffixed. This 0x00 is called the transaction count, but because the headers message doesn’t include any transactions, the transaction count is always zero.

The following annotated hexdump shows a headers message. (The message header has been omitted.)

01 ................................. Header count: 1

02000000 ........................... Block version: 2
b6ff0b1b1680a2862a30ca44d346d9e8
910d334beb48ca0c0000000000000000 ... Hash of previous block's header
9d10aa52ee949386ca9385695f04ede2
70dda20810decd12bc9b048aaab31471 ... Merkle root
24d95a54 ........................... Unix time: 1415239972
30c31b18 ........................... Target (bits)
fe9f0864 ........................... Nonce

00 ................................. Transaction count (0x00)

headers2#

Added in protocol version 70223 of Dash Core.

The headers2 message sends compressed block headers to a node which previously requested certain headers with a getheaders2 message or indicated it wants to receive them by signaling with a sendheaders2 message.

Bytes

Name

Data Type

Description

Varies

count

compactSize uint

Number of block headers up to a maximum of 2,000. Note: headers-first sync assumes the sending node will send the maximum number of headers whenever possible.

Varies

headers

block_header2

Block headers in the block_header2 format
Note: the first header will always be uncompressed.

The following annotated hexdump shows a headers2 message. (The message header has been omitted.)

fdd007 ............................. Header count: 2000 (0x07d0)

Header 1 (uncompressed)
| 38 ............................... Bitfield (0x00100110)
| 02000000 ......................... Block version
| 2cbcf83b62913d56f605c0e581a48872
| 839428c92e5eb76cd7ad94bcaf0b0000 . Hash of previous block's header
| 7f11dcce14075520e8f74cc4ddf092b4
| e26ebd23b8d8665a1ae5bfc41b58fdb4 . Merkle root
| c3a95e53 ......................... Unix time: 1398712771
| ffff0f1e ......................... Target (bits)
| f37a0000 ......................... Nonce

Header 2 (previous header and time compressed)
| 20 ............................... Bitfield (0x00100000)
| 02000000 ......................... Block version
| .................................. Hash of previous block's header (compressed)
| 4d29e4f9b2e05a9ac97dd5ae4128b3c0
| 104bdc95aabaa566cc8eeb682e336d0d . Merkle root
| 0100 ............................. Unix time (compressed)
| f0ff0f1e ......................... Target (bits)
| 7b190000 ......................... Nonce

Header 3 (block version, previous header, time, and bits compressed)
| 01 ............................... Bitfield (0x00000001)
| .................................. Block version (compressed)
| .................................. Hash of previous block's header (compressed)
| 58968247522cc488db01996de610d6f3
| b8c348e748198dc528a305941211c71c . Merkle root
| 0200 ............................. Unix time (compressed)
| .................................. Target (bits) (compressed)
| 7b190000 ......................... Nonce

... Remaining headers truncated

inv#

The inv message (inventory message) transmits one or more inventories of objects known to the transmitting peer. It can be sent unsolicited to announce new transactions or blocks, or it can be sent in reply to a getblocks message or mempool message.

The receiving peer can compare the inventories from an inv message against the inventories it has already seen, and then use a follow-up message to request unseen objects.

Bytes

Name

Data Type

Description

Varies

count

compactSize uint

The number of inventory entries.

Varies

inventory

inventory

One or more inventory entries up to a maximum of 50,000 entries.

The following annotated hexdump shows an inv message with two inventory entries. (The message header has been omitted.)

02 ................................. Count: 2

0f000000 ........................... Type: MSG_MASTERNODE_PING
dd6cc6c11211793b239c2e311f1496e2
2281b200b35233eaae465d2aa3c9d537 ... Hash (mnp)

05000000 ........................... Type: MSG_TXLOCK_VOTE
afc5b2f418f8c06c477a7d071240f5ee
ab17057f9ce4b50c2aef4fadf3729a2e ... Hash (txlvote)

mempool#

Added in protocol version 60002 (of Bitcoin).

The mempool message requests the TXIDs of transactions that the receiving node has verified as valid but which have not yet appeared in a block. That is, transactions which are in the receiving node’s memory pool. The response to the mempool message is one or more inv messages containing the TXIDs in the usual inventory format.

Sending the mempool message is mostly useful when a program first connects to the network. Full nodes can use it to quickly gather most or all of the unconfirmed transactions available on the network; this is especially useful for miners trying to gather transactions for their transaction fees. SPV clients can set a filter before sending a mempool to only receive transactions that match that filter; this allows a recently-started client to get most or all unconfirmed transactions related to its wallet.

📘 InstantSend and ChainLock Synchronization

Dash Core 0.15.0 expanded the mempool message to include syncing of InstantSend Lock inventories. Additionally, nodes now attempt to sync their mempool with peers at startup by default (limited to peers using protocol version 70216 or higher). This allows nodes to more quickly detect any double-spend attempts as well as show InstantSend lock status correctly for transactions received while offline.

Dash Core 0.17.0 expanded the mempool message to include syncing of ChainLock inventories. This allows nodes to more quickly show ChainLock status correctly after being offline.

The inv response to the mempool message is, at best, one node’s view of the network—not a complete list of every unconfirmed transaction on the network. Here are some additional reasons the list might not be complete:

  • The mempool message is not currently fully compatible with the filterload message’s BLOOM_UPDATE_ALL and BLOOM_UPDATE_P2PUBKEY_ONLY flags. Mempool transactions are not sorted like in-block transactions, so a transaction (tx2) spending an output can appear before the transaction (tx1) containing that output, which means the automatic filter update mechanism won’t operate until the second-appearing transaction (tx1) is seen—missing the first-appearing transaction (tx2). It has been proposed in Bitcoin Core issue #2381 that the transactions should be sorted before being processed by the filter.

There is no payload in a mempool message. See the message header section for an example of a message without a payload.

merkleblock#

Added in protocol version 70001 as described by BIP37.

The merkleblock message is a reply to a getdata message which requested a block using the inventory type MSG_MERKLEBLOCK. It is only part of the reply: if any matching transactions are found, they will be sent separately as tx messages. As of Dash Core 18.0.0 isdlock messages for matching transactions are sent if present.

🚧

Note: isdlock messages are currently dropped once a ChainLock is present so in most cases they will not actually be provided in response to a merkleblock request. Future updates may modify this behavior.

If a filter has been previously set with the filterload message, the merkleblock message will contain the TXIDs of any transactions in the requested block that matched the filter, as well as any parts of the block’s merkle tree necessary to connect those transactions to the block header’s merkle root. The message also contains a complete copy of the block header to allow the client to hash it and confirm its proof of work.

Bytes

Name

Data Type

Description

80

block header

block_header

The block header in the format described in the block header section.

4

transaction count

uint32_t

The number of transactions in the block (including ones that don’t match the filter).

Varies

hash count

compactSize uint

The number of hashes in the following field.

Varies

hashes

char[32]

One or more hashes of both transactions and merkle nodes in internal byte order. Each hash is 32 bytes.

Varies

flag byte count

compactSize uint

The number of flag bytes in the following field.

Varies

flags

byte[]

A sequence of bits packed eight in a byte with the least significant bit first. May be padded to the nearest byte boundary but must not contain any more bits than that. Used to assign the hashes to particular nodes in the merkle tree as described below.

The annotated hexdump below shows a merkleblock message which corresponds to the examples below. (The message header has been omitted.)

01000000 ........................... Block version: 1
82bb869cf3a793432a66e826e05a6fc3
7469f8efb7421dc88067010000000000 ... Hash of previous block's header
7f16c5962e8bd963659c793ce370d95f
093bc7e367117b3c30c1f8fdd0d97287 ... Merkle root
76381b4d ........................... Time: 1293629558
4c86041b ........................... nBits: 0x04864c * 256**(0x1b-3)
554b8529 ........................... Nonce

07000000 ........................... Transaction count: 7
04 ................................. Hash count: 4

3612262624047ee87660be1a707519a4
43b1c1ce3d248cbfc6c15870f6c5daa2 ... Hash #1
019f5b01d4195ecbc9398fbf3c3b1fa9
bb3183301d7a1fb3bd174fcfa40a2b65 ... Hash #2
41ed70551dd7e841883ab8f0b16bf041
76b7d1480e4f0af9f3d4c3595768d068 ... Hash #3
20d2a7bc994987302e5b1ac80fc425fe
25f8b63169ea78e68fbaaefa59379bbf ... Hash #4

01 ................................. Flag bytes: 1
1d ................................. Flags: 1 0 1 1 1 0 0 0

Note: when fully decoded, the above merkleblock message provided the TXID for a single transaction that matched the filter. In the network traffic dump this output was taken from, the full transaction belonging to that TXID was sent immediately after the merkleblock message as a tx message.

Parsing A MerkleBlock Message#

As seen in the annotated hexdump above, the merkleblock message provides three special data types: a transaction count, a list of hashes, and a list of one-bit flags.

You can use the transaction count to construct an empty merkle tree. We’ll call each entry in the tree a node; on the bottom are TXID nodes—the hashes for these nodes are TXIDs; the remaining nodes (including the merkle root) are non-TXID nodes—they may actually have the same hash as a TXID, but we treat them differently.

Example Of Parsing A MerkleBlock Message

Keep the hashes and flags in the order they appear in the merkleblock message. When we say “next flag” or “next hash”, we mean the next flag or hash on the list, even if it’s the first one we’ve used so far.

Start with the merkle root node and the first flag. The table below describes how to evaluate a flag based on whether the node being processed is a TXID node or a non-TXID node. Once you apply a flag to a node, never apply another flag to that same node or reuse that same flag again.

Flag

TXID Node

Non-TXID Node

0

Use the next hash as this node’s TXID, but this transaction didn’t match the filter.

Use the next hash as this node’s hash. Don’t process any descendant nodes.

1

Use the next hash as this node’s TXID, and mark this transaction as matching the filter.

The hash needs to be computed. Process the left child node to get its hash; process the right child node to get its hash; then concatenate the two hashes as 64 raw bytes and hash them to get this node’s hash.

Any time you begin processing a node for the first time, evaluate the next flag. Never use a flag at any other time.

When processing a child node, you may need to process its children (the grandchildren of the original node) or further-descended nodes before returning to the parent node. This is expected—keep processing depth first until you reach a TXID node or a non-TXID node with a flag of 0.

After you process a TXID node or a non-TXID node with a flag of 0, stop processing flags and begin to ascend the tree. As you ascend, compute the hash of any nodes for which you now have both child hashes or for which you now have the sole child hash. See the merkle tree section for hashing instructions. If you reach a node where only the left hash is known, descend into its right child (if present) and further descendants as necessary.

However, if you find a node whose left and right children both have the same hash, fail. This is related to CVE-2012-2459.

Continue descending and ascending until you have enough information to obtain the hash of the merkle root node. If you run out of flags or hashes before that condition is reached, fail. Then perform the following checks (order doesn’t matter):

  • Fail if there are unused hashes in the hashes list.

  • Fail if there are unused flag bits—except for the minimum number of bits necessary to pad up to the next full byte.

  • Fail if the hash of the merkle root node is not identical to the merkle root in the block header.

  • Fail if the block header is invalid. Remember to ensure that the hash of the header is less than or equal to the target threshold encoded by the nBits header field. Your program should also, of course, attempt to ensure the header belongs to the best block chain and that the user knows how many confirmations this block has.

For a detailed example of parsing a merkleblock message, please see the corresponding merkle block examples section.

Creating A MerkleBlock Message#

It’s easier to understand how to create a merkleblock message after you understand how to parse an already-created message, so we recommend you read the parsing section above first.

Create a complete merkle tree with TXIDs on the bottom row and all the other hashes calculated up to the merkle root on the top row. For each transaction that matches the filter, track its TXID node and all of its ancestor nodes.

Example Of Creating A MerkleBlock Message

Start processing the tree with the merkle root node. The table below describes how to process both TXID nodes and non-TXID nodes based on whether the node is a match, a match ancestor, or neither a match nor a match ancestor.

TXID Node

Non-TXID Node

Neither Match Nor Match Ancestor

Append a 0 to the flag list; append this node’s TXID to the hash list.

Append a 0 to the flag list; append this node’s hash to the hash list. Do not descend into its child nodes.

Match Or Match Ancestor

Append a 1 to the flag list; append this node’s TXID to the hash list.

Append a 1 to the flag list; process the left child node. Then, if the node has a right child, process the right child. Do not append a hash to the hash list for this node.

Any time you begin processing a node for the first time, a flag should be appended to the flag list. Never put a flag on the list at any other time, except when processing is complete to pad out the flag list to a byte boundary.

When processing a child node, you may need to process its children (the grandchildren of the original node) or further-descended nodes before returning to the parent node. This is expected—keep processing depth first until you reach a TXID node or a node which is neither a TXID nor a match ancestor.

After you process a TXID node or a node which is neither a TXID nor a match ancestor, stop processing and begin to ascend the tree until you find a node with a right child you haven’t processed yet. Descend into that right child and process it.

After you fully process the merkle root node according to the instructions in the table above, processing is complete. Pad your flag list to a byte boundary and construct the merkleblock message using the template near the beginning of this subsection.

mnlistdiff#

Added in protocol version 70213

The mnlistdiff message is a reply to a getmnlistd message which requested either a full masternode list or a diff for a range of blocks.

Bytes

Name

Data
type

Required

Description

2

version

uint16_t

Required

Updated in protocol version 70229
Version of the message (currently 1).
In protocol versions 70225 through 70228 this field was located between the cbTx and deletedMNsCount fields.

32

baseBlockHash

uint256

Required

Hash of a block the requester already has a valid masternode list of. Can be all-zero to indicate that a full masternode list is requested.

32

blockHash

uint256

Required

Hash of the block for which the masternode list diff is requested

4

totalTransactions

uint32_t

Required

Number of total transactions in blockHash

1-9

merkleHashes
Count

compactSize uint

Required

Number of Merkle hashes

variable

merkleHashes

vector

Required

Merkle hashes in depth-first order

1-9

merkleFlags
Count

compactSize uint

Required

Number of Merkle flag bytes

variable

merkleFlags

vector<uint8_t>

Required

Merkle flag bits, packed per 8 in a byte, least significant bit first

variable

cbTx

CTransaction

Required

The fully serialized coinbase transaction of blockHash

1-9

deletedMNsCount

compactSize uint

Required

Number of ProRegTx hashes which were deleted after baseBlockHash

variable

deletedMNs

vector

Required

A list of ProRegTx hashes for masternode which were deleted after baseBlockHash

1-9

mnCount

compactSize uint

Required

Number of SML entries which were added or updated since baseBlockHash

variable

mnList

vector

Required

The list of Simplified Masternode List (SML) entries which were added or updated since baseBlockHash

1-9

deletedQuorums
Count

compactSize uint

Required

Added in protocol version 70214

Number of LLMQs which were deleted from the active set after baseBlockHash

variable

deletedQuorums

(uint8_t+uint256)[]

Required

Added in protocol version 70214

A list of LLMQ type and quorum hashes for LLMQs which were deleted after baseBlockHash

1-9

newQuorumsCount

compactSize uint

Required

Added in protocol version 70214

Number of new LLMQs which were added to the active set since baseBlockHash

variable

newQuorums

qfcommit[]

Required

Added in protocol version 70214

The list of LLMQ commitments for the LLMQs which were added since baseBlockHash

1-9

quorumsCLSigsCount

compactSize uint

Required

Added in protocol version 70230

Number of quorumsCLSigs elements

variable

quorumsCLSigs

quorumsCLSigsObject[]

Required

Added in protocol version 70230

ChainLock signature used to calculate members per quorum indexes (in newQuorums)

Simplified Masternode List (SML) Entry

Bytes

Name

Data type

Description

2

nVersion

uint_16

Added in protocol version 70228
The version of the simplified masternode list

32

proRegTxHash

uint256

The hash of the ProRegTx that identifies the masternode

32

confirmedHash

uint256

The hash of the block at which the masternode got confirmed

16

ipAddress

byte[]

IPv6 address in network byte order. Only IPv4 mapped addresses are allowed (to be extended in the future)

2

port

uint_16

Port (network byte order)

48

pubKeyOperator

BLSPubKey

The operator public key
Note: serialization varies based on nVersion:
- 1 - legacy BLS scheme
- 2 - basic BLS scheme

20

keyIDVoting

CKeyID

The public key hash used for voting.

1

isValid

bool

True if a masternode is not PoSe-banned

0 or 2

type

uint_16

Masternode type:
0 - regular masternode
1 - Evolution masternode
Note: Only present after the Dash v19.0.0 hard fork.

0 or 2

platformHTTPPort

uint_16

TCP port of Platform HTTP/API interface (network byte order).
Note: Only present when mnlistdiff version is 2 and type is 1.

0 or 20

platformNodeID

byte[]

Dash Platform P2P node ID, derived from P2P public key.
Note: Only present when mnlistdiff version is 2 and type is 1.

The content of quorumsCLSigsObject:

Bytes

Name

Data type

Description

96

signature

BLSSig

ChainLock signature

1-9

indexSetCount

compactSize uint

Number of quorum indexes using the same signature for their member calculation

uint16_t[]

indexSet

variable

Quorum indexes corresponding in newQuorums using signature for their member calculation

The following annotated hexdump shows a Dash Core v20.0 mnlistdiff message. (The message header has been omitted.)

0100 ....................................... Message version (1)

de524e1b726ad0d574a15206c24db7cd
6f4d293b3f1c65f3b11523a988020000 ........... Base block hash

4d25794f4e7601e349077d52138c12d3
7761061e83b38426763646d269000000 ........... Block hash

0b000000 ................................... Transactions: 11

05 ......................................... Merkle hash count: 5

a7d9e339ce9f4671c0d16cbfea4acaa5
43cf96f52145b18b447f386cbf7abd4f ........... Merkle hash 1
c71dd34648a0b7040f33b39823f90a96
80f1108d1f07fde1f385d5a91ee1e487 ........... Merkle hash 2
20ec215cf0420a0c5d3e894dc8c49d64
49ab46f1be37d2c7d4a2fed84706d33d ........... Merkle hash 3
51b0c2dbf57f45eb5d6a1341c6ceb199
d4cbf6a63d892a69364a4d254c120f20 ........... Merkle hash 4
72c3210f840aa0d827d63d98456dabf4
2906d0715214735871178b12af8a6eda ........... Merkle hash 5


02 ......................................... Merkle flag count: 2
1f ......................................... Flags: 0 0 0 1 1 1 1 1
00 ......................................... Flags: 0 0 0 0 0 0 0 0

[...]....................................... Coinbase Tx (Not shown)

00 ......................................... Deleted masternodes: 0

00 ......................................... Masternode list entries: 0

03 ......................................... Deleted quorums: 3

Deleted quorums
| 01 ....................................... Quorum type (1)
| e8d70272cb891e97e8302c41e6d72ca0
| c0743624b6797d85bebbc5d311000000 ......... Quorum hash
|
| 04 ....................................... Quorum type (4)
| 16c6383a1fc5a765bd93674c5b9b47cf
| e199589c4258e7b259464e4fea000000 ......... Quorum hash
|
| 06 ....................................... Quorum type (6)
| e8d70272cb891e97e8302c41e6d72ca0
| c0743624b6797d85bebbc5d311000000 ......... Quorum hash

03 ......................................... New quorums: 3

New quorums
| Quorum 1
| | 0300 ................................... Version (3)
| |
| | 01 ..................................... Quorum type (1)
| | 05beb3edd9207ede3a42a15bbd04d597
| | 744f6f9db9b9a68a025c7e5637000000........ Quorum hash
| |
| | 32 ..................................... Signers (50)
| | ffffffffffff03 ......................... Signers bitvector
| |
| | 32 ..................................... Valid members (50)
| | ffffffffffff03 ......................... Valid members bitvector
| |
| | 91e6dfd0d8f33e4306afe0483d7649cc
| | 68b5346f5c658206269083d49d2f1db7
| | 8eedd22eecf748404a1fe12e24f074e1 ....... Quorum public key (BLS)
| |
| | bc7da59621015e70e31310982e66acfe
| | 25468daede7142234e7f3bf3b3297b21 ....... Quorum verification vector hash
| |
| | Quorum threshold signature (BLS)
| | 99f4d8af79cf99ba49c8c9295cbc0827
| | b2b6611a905dc347eec9ecbe6ec6ec64
| | c167ca252f2fc0ff772394c696c58f0c
| | 0e00c4f556ab528e07d06d2e57391fd1
| | 0c57e0521e43f8dfcfc8448665d41eba
| | 7c103b915506476672b531b9ceca266f ....... BLS signature
| |
| | Aggregated signatures from all commitments (BLS)
| | 8f7bb2a10d4cbf6fe7c6cfc1ec52817f
| | 97f025ba9c4c52ac4cfa02ba1c28f3aa
| | fb83c2f4b246f730b5e4aac36e9479d5
| | 0d72db9055dbdc9e2c27dee6f876be66
| | 928abbdf636d1405c59a5e35d4775049
| | 97f0e3b5acd2c53448deaaf61fed9343 ....... BLS signature
|
| [...] .................................... Remaining quorums truncated

01 ......................................... ChainLock signature count
ChainLock signature object
| ae1ccf19235d06ae370f3538796525c1
| d8e404252b0a91109c031d60f7d0c740
| 7e5678b1ea4792ff32fffdafb061bf1d
| 0c7a53afa399e203719e73cee1c0640d
| ca24fb16f6950f7aba1b655f7fa195d8
| 0476e65b987bc51689d7946680b04dcf ......... ChainLock signature
| 
| 03 ....................................... Index set count (3)
|
| Index set
| | 0000 ................................... Quorum index (0)
| | 0100 ................................... Quorum index (1)
| | 0200 ................................... Quorum index (2)

notfound#

Added in protocol version 70001.

The notfound message is a reply to a getdata message which requested an object the receiving node does not have available for relay. (Nodes are not expected to relay historic transactions which are no longer in the memory pool or relay set. Nodes may also have pruned spent transactions from older blocks, making them unable to send those blocks.)

The format and maximum size limitations of the notfound message are identical to the inv message; only the message header differs.

qrinfo#

Added in protocol version 70222 of Dash Core.

The qrinfo message sends quorum rotation information to a node which previously requested it with a getqrinfo message.

Note: In the following fields, c refers to the quorum cycle length. This is synonymous with the DKG interval (quorumDkgInterval) as defined in DIP6.

Bytes

Name

Data type

Required

Description

Varies

quorumSnapshot
AtHMinusC

CQuorumSnapshot

Required

Quorum snapshot for height h-c

Varies

quorumSnapshot
AtHMinus2C

CQuorumSnapshot

Required

Quorum snapshot for height h-2c

Varies

quorumSnapshot
AtHMinus3C

CQuorumSnapshot

Required

Quorum snapshot for height h-3c

Varies

mnListDiffTip

CSimplifiedMNListDiff
(see mnlistdiff)

Required

Masternode list diff at height at the tip.

Varies

mnListDiffH

CSimplifiedMNListDiff
(see mnlistdiff)

Required

Masternode list diff at height h.

Varies

mnListDiff
AtHMinusC

CSimplifiedMNListDiff
(see mnlistdiff)

Required

Masternode list diff at height h-c

Varies

mnListDiff
AtHMinus2C

CSimplifiedMNListDiff
(see mnlistdiff)

Required

Masternode list diff at height h-2c

Varies

mnListDiff
AtHMinus3C

CSimplifiedMNListDiff
(see mnlistdiff)

Required

Masternode list diff at height h-3c

1

extraShare

bool

Required

Flag to indicate if an extra share is requested

Varies

quorumSnapshot
AtHMinus4C

CQuorumSnapshot

Optional

Returned only if extraShare is on. See below for sub-message contents.

Varies

mnListDiff
AtHMinus4C

CSimplifiedMNListDiff

Optional

Returned only if extraShare is on. As in DIP-4.

1-9

lastQuorumHashPer
IndexSize

compactSize uint

Required

Number of elements in lastCommitmentPerIndex

32 * lastQuorum
HashPer
IndexSize

lastCommitment
PerIndex

uint256_t[]

Required

Contains the most recent commitment for each quorumIndex. Ordered by quorumIndex.

1-9

quorumSnapshot
ListSize

compactSize uint

Required

Number of elements in quorumSnapshotList

Varies

quorumSnapshot
List

CQuorumSnapshot[]

Required

The snapshots required to reconstruct the quorums built at h in heightsLists. Ordered from oldest to newest

1-9

mnListDiff
ListSize

compactSize uint

Required

Number of elements in mnListDiffList

Varies

mnListDiffList

CSimplifiedMNListDiff[]

Required

The MNLISTDIFFs required to calculate older quorums. Ordered from oldest to newest

CQuorumSnapshot

Note: All fields are required

Bytes

Name

Data type

Description

4

mnSkipListMode

int32_t

Mode of the skip list

1-9

activeQuorum
MembersSize

compactSize uint

Number of elements in activeQuorumMembers

(activeQuorum
MembersSize) + 7)/8

activeQuorumMembers

cbitset

The bitset of nodes already in quarters at the start of cycle at height n

1-9

mnSkipListSize

compactSize uint

Number of elements in mnSkipList

4 * mnSkipListSize

mnSkipList

int32_t[]

Skiplist at height n

The following annotated hexdump shows a qrinfo message. (The message header has been omitted.)

Quorum snapshot (h-c)
| 01000000 ................................. Skiplist mode: 1
| 1f ....................................... Active quorum members: 31
| bbffff7f ................................. Active quorum members bitset
| 
| 01 ....................................... Skip list size: 1
| 
| Skip list
| | 0b000000 ............................... Masternode 11

Quorum snapshot (h-2c)
| 01000000 ................................. Skiplist mode: 1
| 1f ....................................... Active quorum members: 31
| f3ff6f7b ................................. Active quorum members bitset
|
| 06 ....................................... Skip list size: 6
| 
| Skip list
| | 05000000 ............................... Masternode 5
| | 03000000 ............................... Masternode 3
| | 04000000 ............................... Masternode 4
| | 06000000 ............................... Masternode 6
| | 07000000 ............................... Masternode 7
| | 08000000 ............................... Masternode 8

Quorum snapshot (h-3c) ..................... Not shown for brevity

MnListDiff (Tip)
| e173b01943fe7b8d2bf5a13c034eafed
| d2708a1a0f9e5104b86439382e050000 ......... Base block hash
| 847b42ae4509c82e8c8ba599f23f15c1
| e34c899a09e4ebf440f6e2ef4b000000 ......... Block hash
| 01000000 ................................. Transactions: 1
| 01 ....................................... Merkle hash count: 1
| c44c59fd87c816506d3890aaf0c8f7df
| bad10f4a9b3e2b43bc1e9c832e81b381 ......... Merkle hash 1
| 01 ....................................... Merkle flag count: 1
| 01 ....................................... Flags: 0 0 0 0 0 0 0 1
|
| [...]..................................... Coinbase Tx (Not shown)

MnListDiff (h) ............................. Not shown for brevity
MnListDiff (h-c) ........................... Not shown for brevity
MnListDiff (h-2c) .......................... Not shown for brevity
MnListDiff (h-3c) .......................... Not shown for brevity

01 ....................................... Extra share: true

Quorum snapshot (h-4c)
| 01000000 ................................. Skiplist mode: 1
| 1f ....................................... Active quorum members: 31
| ff7fdd5f ................................. Active quorum members bitset
|
| 01 ....................................... Skip list size: 1
|
| Skip list
| | 07000000 ............................... Masternode 7

MnListDiff (h-4c)

Last quorum hash per index
| 04 ....................................... Quorum hashes: 4
| c2e276c518b3f8484b237e300094e222
| 388a095f486c822585a67b1520010000 ......... Quorum hash 1
| bb4f0c5a3efb229bd5a4e4e45ca2228e
| b11f05c3a6e8fdf9d7d4f499b7010000 ......... Quorum hash 2
| aca22eb2c63daa5304cb9cbe6089afe3
| 99e335f73306735718355ad3d9000000 ......... Quorum hash 3
| 45bf29bada522857d6e3b2371e1fefc7
| c01fcef0b6578e7062fd571760010000 ......... Quorum hash 4

00 ......................................... Quorum snapshot list size: 0
00 ......................................... Masternode list diff list size: 0

tx#

The tx message transmits a single transaction in the raw transaction format. It can be sent in a variety of situations;

For an example hexdump of the raw transaction format, see the raw transaction section.