The Special Transactions framework established by DIP2 enabled the implementation of new on-chain features and consensus mechanisms. These transactions provide the flexibility to expand beyond the financial uses of classical transactions. DIP2 transactions modified classical transactions by:

Splitting the 32 bit version field into two 16 bit fields (version and type)
Adding support for a generic extra payload following the lock_time field. The maximum allowed size for a transaction version 3 extra payload is 10000 bytes (MAX_TX_EXTRA_PAYLOAD).

Classical (financial) transactions have a type of 0 while special transactions have a type defined in the DIP describing them. A list of current special transaction types is maintained in the DIP repository.

Implemented Special Transactions

Release	Tx Version	Tx Type	Payload JSON	Tx Purpose	Payload
v0.12.3	2	-	n/a	n/a	n/a
v0.13.0	3	0	n/a	Standard (Classical) Transaction	n/a
v0.13.0	3	1	ProRegTx	Masternode Registration	hex
v0.13.0	3	2	ProUpServTx	Update Masternode Service	hex
v0.13.0	3	3	ProUpRegTx	Update Masternode Operator	hex
v0.13.0	3	4	ProUpRevTx	Masternode Operator Revocation	hex
v0.13.0	3	5	CbTx	Masternode List Merkle Proof	hex
v0.13.0	3	6	QcTx	Long-Living Masternode Quorum Commitment	hex

ProRegTx

Added in protocol version 70213 of Dash Core as described by DIP3

The masternode Registration (ProRegTx) special transaction is used to join the masternode list by proving ownership of the 1000 DASH necessary to create a masternode.

A ProRegTx is created and sent using the protx RPC. The ProRegTx must either include an output with 1000 DASH (protx register) or refer to an existing unspent output holding 1000 DASH (protx fund_register). If the 1000 DASH is an output of the ProRegTx, the collateralOutpoint hash field should be null.

The special transaction type is 1 and the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	Provider transaction version number. Currently set to 1.
2	type	uint_16	Masternode type. Default set to 0.
2	mode	uint_16	Masternode mode. Default set to 0.
36	collateralOutpoint	COutpoint	The collateral outpoint. Note: The hash will be null if the collateral is part of this transaction, otherwise it will reference an existing collateral.
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)
20	KeyIdOwner	CKeyID	The public key hash used for owner related signing (ProTx updates, governance voting)
48	PubKeyOperator	CBLSPublicKey	The BLS public key used for operational related signing (network messages, ProTx updates)
20	KeyIdVoting	CKeyID	The public key hash used for voting.
2	operatorReward	uint_16	A value from 0 to 10000.
1-9	scriptPayoutSize	compactSize uint	Size of the Payee Script.
Variable	scriptPayout	Script	Payee script (p2pkh/p2sh)
32	inputsHash	uint256	Hash of all the outpoints of the transaction inputs
1-9	payloadSigSize	compactSize uint	Size of the Signature
Variable	payloadSig	vector	Signature of the hash of the ProTx fields. Signed with the key corresponding to the collateral outpoint in case the collateral is not part of the ProRegTx itself, empty otherwise.

The following annotated hexdump shows a ProRegTx transaction referencing an existing collateral. (Parts of the classical transaction section have been omitted.)

0300 ....................................... Version (3)
0100 ....................................... Type (1 - ProRegTx)

[...] ...................................... Transaction inputs omitted
[...] ...................................... Transaction outputs omitted

00000000 ................................... locktime: 0 (a block height)

fd1201 ..................................... Extra payload size (274)

ProRegTx Payload
| 0100 ..................................... Version (1)
| 0000 ..................................... Type (0)
| 0000 ..................................... Mode (0)
|
| 4859747b0eb19bb2dae5a12ef7b6a69b
| 03712bfeded1174de0b6ab1334ab2e8b ......... Outpoint TXID
| 01000000 ................................. Outpoint index number: 1
|
| 00000000000000000000ffffc0000233 ......... IP Address: ::ffff:192.0.2.51
| 270f ..................................... Port: 9999
|
|
| 1636e84d02310b0b458f3eb51d8ea8b2e684b7ce . Owner pubkey hash (ECDSA)
| 88d719278eef605d9c19037366910b59bc28d437
| de4a8db4d76fda6d6985dbdf10404fb9bb5cd0e8
| c22f4a914a6c5566 ......................... Operator public key (BLS)
| 1636e84d02310b0b458f3eb51d8ea8b2e684b7ce . Voting pubkey hash (ECDSA)
|
| f401 ..................................... Operator reward (500 -> 5%)
|
| Payout script
| 19 ....................................... Bytes in pubkey script: 25
| | 76 ..................................... OP_DUP
| | a9 ..................................... OP_HASH160
| | 14 ..................................... Push 20 bytes as data
| | | fc136008111fcc7a05be6cec66f97568
| | | 727a9e51 ............................. PubKey hash
| | 88 ..................................... OP_EQUALVERIFY
| | ac ..................................... OP_CHECKSIG
|
| 0fcfb7d939078ba6a6b81ecf1dc2e05d
| e2776f49f7b503ac254798be6a672699 ......... Inputs hash
|
| Payload signature
| 41 ....................................... Signature Size (65)
| 200476f193b465764093014ba44bd4ff
| de2b3fc92794c4acda9cad6305ca172e
| 9e3d6b1cd6e30f86678dae8e6595e53d
| 2b30bc32141b6c0151eb58479121b3e6a4 ....... Signature

The following annotated hexdump shows a ProRegTx transaction creating a new collateral.

Note the presence of the output, a null Outpoint TXID and the absence of a signature (since it isn't referring to an existing collateral). (Parts of the classical transaction section have been omitted.)

0300 ....................................... Version (3)
0100 ....................................... Type (1 - ProRegTx)

[...] ...................................... Transaction inputs omitted

02 ......................................... Number of outputs
| [...] .................................... 1 output omitted
|
| Masternode collateral output
| | 00e8764817000000 ....................... Duffs (1000 DASH)
| | 1976a9149e648c7e4b61482aa3
| | 9bd10e0bf0b5268768005f88ac ............. Script

00000000 ................................... locktime: 0 (a block height)

d1 ......................................... Extra payload size (209)

ProRegTx Payload
| 0100 ..................................... Version (1)
| 0000 ..................................... Type (0)
| 0000 ..................................... Mode (0)
|
| 00000000000000000000000000000000
| 00000000000000000000000000000000 ......... Outpoint TXID
| 01000000 ................................. Outpoint index number: 1
|
| 00000000000000000000ffffc0000233 ......... IP Address: ::ffff:192.0.2.51
| 270f ..................................... Port: 9999
|
| 757a2171bbf92517e358249f20c37a8ad2d7a5bc . Owner pubkey hash (ECDSA)
| 0e02146e9c34cfbcb3f3037574a1abb35525e2ca
| 0c3c6901dbf82ac591e30218d1711223b7ca956e
| df39f3d984d06d51 ......................... Operator public key (BLS)
| 757a2171bbf92517e358249f20c37a8ad2d7a5bc . Voting pubkey hash (ECDSA)
|
| f401 ..................................... Operator reward (500 -> 5%)
|
| Payout script
| 19 ....................................... Bytes in pubkey script: 25
| | 76 ..................................... OP_DUP
| | a9 ..................................... OP_HASH160
| | 14 ..................................... Push 20 bytes as data
| | | 9e648c7e4b61482aa39bd10e0bf0b526
| | | 8768005f ............................. PubKey hash
| | 88 ..................................... OP_EQUALVERIFY
| | ac ..................................... OP_CHECKSIG
|
| 57b115d681b9aff82824ff7e22af99d4
| ac4b39ad7be7cb70b662e9011827d589 ......... Inputs hash
|
| Payload signature
| 00 ....................................... Signature Size (0)
| .......................................... Signature (Empty)

ProUpServTx

Added in protocol version 70213 of Dash Core as described by DIP3

The masternode Provider Update Service (ProUpServTx) special transaction is used to update the IP Address and port of a masternode. If a non-zero operatorReward was set in the initial ProRegTx, the operator may also set the scriptOperatorPayout field in the ProUpServTx.

A ProUpServTx is only valid for masternodes in the registered masternodes subset. When processed, it updates the metadata of the masternode entry and revives the masternode if it was previously marked as PoSe-banned.

A ProUpServTx is created and sent using the protx update_service RPC.

The special transaction type used for ProUpServTx Transactions is 2 and the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	ProUpServTx version number. Currently set to 1.
32	proTXHash	uint256	The hash of the initial ProRegTx
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)
1-9	scriptOperator PayoutSize	compactSize uint	Size of the Operator Payee Script.
Variable	scriptOperator Payout	Script	Operator Payee script (p2pkh/p2sh)
32	inputsHash	uint256	Hash of all the outpoints of the transaction inputs
1-9	payloadSigSize	compactSize uint	Size of the Signature Note: not present in BLS implementation
96	payloadSig	vector	BLS Signature of the hash of the ProUpServTx fields. Signed by the Operator.

The following annotated hexdump shows a ProUpServTx transaction. (Parts of the
classical transaction section have been omitted.)

0300 ....................................... Version (3)
0200 ....................................... Type (2 - ProUpServTx)

[...] ...................................... Transaction inputs omitted
[...] ...................................... Transaction outputs omitted

00000000 ................................... locktime: 0 (a block height)

b5 ......................................... Extra payload size (181)

ProUpServTx Payload
| 0100 ..................................... Version (1)
|
| db60b8cecae691a3d078a2341d460b06
| b2914f6b092f1906b5c815589399b0ff ......... ProRegTx Hash
|
| 00000000000000000000ffffc0000233 ......... IP Address: ::ffff:192.0.2.51
| 270f ..................................... Port: 9999
|
| 00 ....................................... Operator payout script size (0)
| .......................................... Operator payout script (Empty)
|
| a9569d037b0eacc8bca05c5829c95283
| 4ac27d1c7e7df610500b7ba70fd46507 ......... Inputs hash
|
| Payload signature (BLS)
| 0267702ef85d186ef7fa32dc40c65f2f
| eca0a7465715eb7c30f81beb69e35ee4
| 1f6ff7f292b82a9caebb5aa961b0f915
| 02501becf629e93c0a01c76162d56a6c
| 65a9675c3ca9d5297f053e68f91393dd
| 789beed8ef7e8839695a334c2e1bd37c ......... BLS Signature (96 bytes)

ProUpRegTx

Added in protocol version 70213 of Dash Core as described by DIP3

The masternode Provider Update Registrar (ProUpRegTx) special transaction is used by a masternode owner to update masternode metadata (e.g. operator/voting key details or the payout script).

A ProUpRegTx is created and sent using the protx update_registrar RPC.

The special transaction type is 3 and the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	Provider update registrar transaction version number. Currently set to 1.
32	proTXHash	uint256	The hash of the initial ProRegTx
2	mode	uint_16	Masternode mode. Default set to 0.
48	PubKeyOperator	CBLSPublicKey	The BLS public key used for operational related signing (network messages, ProTx updates)
20	KeyIdVoting	CKeyID	The public key hash used for voting.
1-9	scriptPayoutSize	compactSize uint	Size of the Payee Script.
Variable	scriptPayout	Script	Payee script (p2pkh/p2sh)
32	inputsHash	uint256	Hash of all the outpoints of the transaction inputs
1-9	payloadSigSize	compactSize uint	Size of the Signature
Variable	payloadSig	vector	Signature of the hash of the ProTx fields. Signed with the key corresponding to the collateral outpoint in case the collateral is not part of the ProRegTx itself, empty otherwise.

The following annotated hexdump shows a ProUpRegTx transaction referencing an
existing collateral. (Parts of the classical transaction section have been omitted.)

0300 ....................................... Version (3)
0300 ....................................... Type (3 - ProUpRegTx)

[...] ...................................... Transaction inputs omitted
[...] ...................................... Transaction outputs omitted

00000000 ................................... locktime: 0 (a block height)

e4 ......................................... Extra payload size (228)

ProRegTx Payload
| 0100 ..................................... Version (1)
|
| ddaf13bf1b02de39711de911e646c63e
| f089b6cee786a1b776086ae130331bba ......... ProRegTx Hash
|
| 0000 ..................................... Mode (0)
|
| 0e02146e9c34cfbcb3f3037574a1abb35525e2ca
| 0c3c6901dbf82ac591e30218d1711223b7ca956e
| df39f3d984d06d51 ......................... Operator public key (BLS)
| 757a2171bbf92517e358249f20c37a8ad2d7a5bc . Voting pubkey hash (ECDSA)
|
| Payout script
| 19 ....................................... Bytes in pubkey script: 25
| | 76 ..................................... OP_DUP
| | a9 ..................................... OP_HASH160
| | 14 ..................................... Push 20 bytes as data
| | | 9e648c7e4b61482aa39bd10e0bf0b526
| | | 8768005f ............................. PubKey hash
| | 88 ..................................... OP_EQUALVERIFY
| | ac ..................................... OP_CHECKSIG
|
| 50b50b24193b2b16f0383125c1f4426e
| 883d256eeadee96d500f8c08b0e0f9e4 ......... Inputs hash
|
| Payload signature
| 41 ....................................... Signature Size (65)
| 1ffa8a27ae0301e414176d4c876cff2e
| 20b810683a68ab7dcea95de1f8f36441
| 4c56368f189a3ef7a59b83bd77f22431
| a73d347841a58768b94c771819dc2bbce3 ....... Signature

ProUpRevTx

Added in protocol version 70213 of Dash Core as described by DIP3

The masternode Operator Revocation (ProUpRevTx) special transaction allows an operator to revoke their key in case of compromise or if they wish to terminate service. If a masternode's operator key is revoked, the masternode becomes ineligible for payment until the owner provides a new operator key (via a ProUpRegTx).

A ProUpRevTx is created and sent using the protx revoke RPC.

The special transaction type used for ProUpServTx Transactions is 4 and the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	ProUpRevTx version number. Currently set to 1.
32	proTXHash	uint256	The hash of the initial ProRegTx
2	reason	uint_16	The reason for revoking the key. `0` - Not specified `1` - Termination of Service `2` - Compromised Key `3` - Change of key
32	inputsHash	uint256	Hash of all the outpoints of the transaction inputs
1-9	payloadSigSize	compactSize uint	Size of the Signature Note: not present in BLS implementation
96	payloadSig	vector	BLS Signature of the hash of the ProUpServTx fields. Signed by the Operator.

The following annotated hexdump shows a ProUpRevTx transaction. (Parts of the classical transaction section have been omitted.)

0300 ....................................... Version (3)
0400 ....................................... Type (4 - ProUpRevTx)

[...] ...................................... Transaction inputs omitted
[...] ...................................... Transaction outputs omitted

00000000 ................................... locktime: 0 (a block height)

a4 ......................................... Extra payload size (164)

ProUpRevTx Payload
| 0100 ..................................... Version (1)
|
| ddaf13bf1b02de39711de911e646c63e
| f089b6cee786a1b776086ae130331bba ......... ProRegTx Hash
|
| 0000 ..................................... Reason: 0 (Not specified)
|
| cb0dfe113c87f8e9cde2c5d18aae12fc
| 8d0617c42c34ca5c2f2f6ab4b1dae164 ......... Inputs hash
|
| Payload signature (BLS)
| 0adaef4bf1a904308f1b0efbdfaffc93
| 864f9e047fd83415c831589180303711
| 0f0d8adb312ab43ddd7f8086042d3f5b
| 09029a6a16c341c9d2a62789b495fef4
| e068da711dac28106ff354db7249ae88
| 05877d82ff7d1af00ae2d303dea5eb3b ......... BLS Signature (96 bytes)

CbTx

Added in protocol version 70213 of Dash Core as described by DIP4

The Coinbase (CbTx) special transaction adds information to the block coinbase transaction that enables verification of the deterministic masternode list without the full chain (e.g. from SPV clients). This allows light-clients to properly verify InstantSend transactions and support additional deterministic masternode list functionality in the future.

The special transaction type used for CbTx Transactions is 5 and the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	CbTx version number. Currently set to 1.
4	height	uint32_t	Height of the block
32	merkleRootMNList	uint256	Merkle root of the masternode list
32	merkleRootQuorums	uint256	Added by CbTx version 2 in v0.14.0 Merkle root of currently active LLMQs

Version History

CbTx Version	First Supported Protocol Version	Dash Core Version	Notes
1	70213	0.13.0	Enabled by activation of DIP3
2	70214	0.14.0	Enabled by activation of DIP8

The following annotated hexdump shows a CbTx transaction.

An itemized coinbase transaction:

0300 ....................................... Version (3)
0500 ....................................... Type (5 - Coinbase)

01 ......................................... Number of inputs
| 00000000000000000000000000000000
| 00000000000000000000000000000000 ......... Previous outpoint TXID
| ffffffff ................................. Previous outpoint index
|
| 4c ....................................... Bytes in coinbase: 76
| |
| | 03 ..................................... Bytes in height
| | | 393d01 ............................... Height: 81209
| |
| | 04b9...6d2f ............................ Arbitrary data (truncated)
| 00000000 ................................. Sequence

02 ......................................... Output count
| Transaction Output 1
| | 40230e4300000000 ....................... Duffs (11.25 DASH)
| | 1976a914b7ce0ea9ce2010f58ba4aaa6
| | caa76671c438e89088ac ................... Script
|
| Transaction Output 2
| | 40230e4300000000 ....................... Duffs (11.25 DASH)
| | 1976a91405ea03a6c9dfa67e1837b3c1
| | 4965ba3cb53bce7288ac ................... P2PKH script

00000000 ................................... Locktime

46 ......................................... Extra payload size (38)

Coinbase Transaction Payload
| 0200 ..................................... Version (2)
|
| 393d0100 ................................. Block height: 81209
|
| e2dd012c5b0b1753cef0e32f978917ef
| e7a484c5080b31b4e3f966ccc0e0f8dd ......... MN List merkle root
|
| 2ef709f55fa42cb53d29d75dad77d212
| fb0bd72a47ecfe0e8aa6f660fb96396e ......... Active LLMQ merkle root

QcTx

Added in protocol version 70213 of Dash Core as described by DIP6

🚧
Note
This special transaction has no inputs and no outputs and thus also pays no fee

The Quorum Commitment (QcTx) special transaction adds the best final commitment from a Long-Living Masternode Quorum (LLMQ) Distributed Key Generation (DKG) session to the chain.

Since this special transaction pays no fees, it is mandatory by consensus rules to ensure that miners include it. Exactly one quorum commitment transaction MUST be included in every block while in the mining phase of the LLMQ process until a valid commitment is present in a block.

If a DKG failed or a miner did not receive a final commitment in-time, a null commitment has to be included in the special transaction payload. A null commitment must have the signers and validMembers bitsets set to the quorumSize and all bits set to zero. All other fields must be set to the null representation of the field’s types.

The special transaction type used for Quorum Commitment Transactions is 6 and
the extra payload consists of the following data:

Bytes	Name	Data type	Description
2	version	uint_16	Quorum Commitment version number. Currently set to 1.
4	height	uint32_t	Height of the block
Variable	commitment	qfcommit	The payload of the `qfcommit` message

The following annotated hexdump shows a QcTx transaction.

An itemized quorum commitment transaction:

0300 ....................................... Version (3)
0600 ....................................... Type (6 - Quorum Commitment)

00 ......................................... Number of inputs
00 ......................................... Number of outputs

00000000 ................................... Locktime

fd4901 ..................................... Extra payload size (329)

Quorum Commitment Transaction Payload
| 0100 ..................................... Version (1)
|
| 934c0100 ................................. Block height: 85139
|
| Payload from the qfcommit message
| | 0100 ................................... Version (1)
| |
| | 01 ..................................... LLMQ Type (1)
| |
| | 6b2fd2c61cea32d939ee7fe185c7abc5
| | 01aa7001d973379f46b9200500000000 ....... Quorum hash
| |
| | 32 ..................................... Number of signers (50)
| | bfffffffffff03 ......................... Aggregrated signers bitvector
| |
| | 32 ..................................... Number of valid members (50)
| | bfffffffffff03 ......................... Valid members bitvector
| |
| | 9450e90f61a24a4205c92572666ed068
| | 40f617ac11a26d650c88769675e81197
| | 993858d8b695f120f0af7dd38c17a67e ....... Quorum public key (BLS)
| |
| | 912507814fe204c59e14720bc961c09f
| | f88a4fd1f15e9c2efd4e4f112720967d ....... Quorum verification vector hash
| |
| | Quorum threshold signature (BLS)
| | 0281c321090c2d2e59a0d3754dcfbc11
| | d76c26a152b50885d826915af4d95a73
| | 120d0e1ba7e96d89f40252e24109c323
| | 0971dda1f554d331985ca570c76b9a1a
| | ec699ec132838ae097c767d65d0a51d7
| | 017c62e062270b60b854ae912bc07437 ....... BLS Signatures (96 bytes)
| |
| | Aggregated signatures from all commitments (BLS)
| | 91f878a0ae620e2178bff06c3a3967d7
| | 433d4b82e7879bb927dd5cb605423c84
| | 0641fcddf3731da80d0515a172ff3666
| | 0f4eac88ee8fd7779e32e4f0be704078
| | df31601b87b95374cebb4b304afc543e
| | e0d4f461a2ba0e32a711197ca559dacf ....... BLS Signature (96 bytes)

ProRegTx

ProUpServTx

ProUpRegTx

ProUpRevTx

CbTx

QcTx

🚧Note

🚧
Note