dash/dash-docs/protocol-documentation.md

Protocol Documentation - 0.12.1

This document describes the protocol extensions for all additional functionality build into the Dash protocol. This doesn't include any of the Bitcoin procotol, which has been left in tact in the Dash project. For more information about the core protocol, please see https://en.bitcoin.it/w/index.php?title#Protocol_documentation&action#edit

Common Structures

Simple types

uint256 => char[32]

CScript => uchar[]

COutPoint

Bitcoin Outpoint https://bitcoin.org/en/glossary/outpoint

Field Size	Field Name	Data type	Description
32	hash	uint256	Hash of transactional output which is being referenced
4	n	uint32_t	Index of transaction which is being referenced

CTxIn

Bitcoin Input https://bitcoin.org/en/glossary/input

Field Size	Field Name	Data type	Description
36	prevout	COutPoint	The previous output from an existing transaction, in the form of an unspent output
1+	script length	var_int	The length of the signature script
?	script	CScript	The script which is validated for this input to be spent
4	nSequence	uint_32t	Transaction version as defined by the sender. Intended for "replacement" of transactions when information is updated before inclusion into a block.

CTxOut

Bitcoin Output https://bitcoin.org/en/glossary/output

Field Size	Field Name	Data type	Description
8	nValue	int64_t	Transfered value
?	scriptPubKey	CScript	The script for indicating what conditions must be fulfilled for this output to be further spent

CPubKey

Bitcoin Public Key https://bitcoin.org/en/glossary/public-key

Field Size	Field Name	Data type	Description
33-65	vch	char[]	The public portion of a keypair which can be used to verify signatures made with the private portion of the keypair.

Message Types

MNANNOUNCE - "mnb"

CMasternodeBroadcast

Whenever a masternode comes online or a client is syncing, they will send this message which describes the masternode entry and how to validate messages from it.

Field Size	Field Name	Data type	Description
41	vin	CTxIn	The unspent output which is holding 1000 DASH
#	addr	CService	Address of the main 1000 DASH unspent output
33-65	pubKeyCollateralAddress	CPubKey	CPubKey of the main 1000 DASH unspent output
33-65	pubKeyMasternode	CPubKey	CPubKey of the secondary signing key (For all other messaging other than announce message)
71-73	sig	char[]	Signature of this message
8	sigTime	int64_t	Time which the signature was created
4	nProtocolVersion	int	The protocol version of the masternode
#	lastPing	CMasternodePing	The last known ping of the masternode
8	nLastDsq	int64_t	The last time the masternode sent a DSQ message (for mixing) (DEPRECATED)

MNPING - "mnp"

CMasternodePing

Every few minutes, masternodes ping the network with a message that propagates the whole network.

Field Size	Field Name	Data type	Description
41	vin	CTxIn	The unspent output of the masternode which is signing the message
32	blockHash	uint256	Current chaintip blockhash minus 12
8	sigTime	int64_t	Signature time for this ping
71-73	vchSig	char[]	Signature of this message by masternode (verifiable via pubKeyMasternode)

MASTERNODEPAYMENTVOTE - "mnw"

CMasternodePaymentVote

When a new block is found on the network, a masternode quorum will be determined and those 10 selected masternodes will issue a masternode payment vote message to pick the next winning node.

Field Size	Field Name	Data type	Description
41	vinMasternode	CTxIn	The unspent output of the masternode which is signing the message
4	nBlockHeight	int	The blockheight which the payee should be paid
?	payeeAddress	CScript	The address to pay to
71-73	sig	char[]	Signature of the masternode which is signing the message

DSTX - "dstx"

CDarksendBroadcastTx

Masternodes can broadcast subsidised transactions without fees for the sake of security in mixing. This is done via the DSTX message.

Field Size	Field Name	Data type	Description
#	tx	CTransaction	The transaction
41	vin	CTxIn	Masternode unspent output
71-73	vchSig	char[]	Signature of this message by masternode (verifiable via pubKeyMasternode)
8	sigTime	int64_t	Time this message was signed

DSSTATUSUPDATE - "dssu"

Mixing pool status update

Field Size	Field Name	Data type	Description
4	nMsgSessionID	int	Session ID
4	nMsgState	int	Current state of mixing process
4	nMsgEntriesCount	int	Number of entries in the mixing pool
4	nMsgStatusUpdate	int	Update state and/or signal if entry was accepted or not
4	nMsgMessageID	int	ID of the typical masternode reply message

DSQUEUE - "dsq"

CDarksendQueue

Asks users to sign final mixing tx message.

Field Size	Field Name	Data type	Description
4	nDenom	int	Which denomination is allowed in this mixing session
41	vin	CTxIn	unspend output from masternode which is hosting this session
4	nTime	int	the time this DSQ was created
4	fReady	int	if the mixing pool is ready to be executed
71-73	vchSig	char[]	Signature of this message by masternode (verifiable via pubKeyMasternode)

DSACCEPT - "dsa"

Response to DSQ message which allows the user to join a mixing pool

Field Size	Field Name	Data type	Description
4	nDenom	int	denomination that will be exclusively used when submitting inputs into the pool
41+	txCollateral	int	collateral tx that will be charged if this client acts maliciousely

DSVIN - "dsi"

CDarkSendEntry

When queue is ready user is expected to send his entry to start actual mixing

Field Size	Field Name	Data type	Description
?	vecTxDSIn	CTxDSIn[]	vector of users inputs (CTxDSIn serialization is equal to CTxIn serialization)
8	nAmount	int64_t	depreciated since 12.1, it's used for backwards compatibility only and can be removed with future protocol bump
?	txCollateral	CTransaction	Collateral transaction which is used to prevent misbehavior and also to charge fees randomly
?	vecTxDSOut	CTxDSOut[]	vector of user outputs (CTxDSOut serialization is equal to CTxOut serialization)

DSSIGNFINALTX - "dss"

User's signed inputs for a group transaction in a mixing session

Field Size	Field Name	Data type	Description
#	inputs	CTxIn[]	signed inputs for mixing session

MNGOVERNANCEOBJECT - "govobj"

Governance Object

A proposal, contract or setting.

Field Size	Field Name	Data type	Description
32	nHashParent	uint256	Parent object, 0 is root
4	nRevision	int	Object revision in the system
8	nTime	int64_t	Time which this object was created
32	nCollateralHash	uint256	Hash of the collateral fee transaction
0-16384	strData	string	Data field - can be used for anything
4	nObjectType	int	????
41	vinMasternode	CTxIn	Unspent output for the masternode which is signing this object
71-73	vchSig	char[]	Signature of the masternode

MNGOVERNANCEOBJECTVOTE - "govobjvote"

Governance Vote

Masternodes use governance voting in response to new proposals, contracts, settings or finalized budgets.

Field Size	Field Name	Data type	Description
4	nVoteSignal	int	???
41+	vinMasternode	CTxIn	Unspent output for the masternode which is voting
32	nParentHash	uint256	Object which we're voting on (proposal, contract, setting or final budget)
4	nVoteOutcome	int	???
8	nTime	int64_t	Time which the vote was created
71-73	vchSig	char[]	Signature of the masternode