Proof of Service#

The Proof of Service (PoSe) scoring system helps incentivize masternodes to provide network services. Masternodes that neglect to participate receive an increased PoSe score which eventually results in them being excluded from masternode payment eligibility.

Distributed Key Generation Participation Requirements#

The following table lists the aspects of the DKG process a masternode must comply with to avoid receiving a PoSe score increase:

Protocol Version

Proof of Service
Requirement

70213+

Exchange required messages (quorum contributions and quorum justifications) with other quorum members during the LLMQ DKG process (Dash Core 0.13.0+)

70218+

Have an open P2P port (Dash Core 0.16.0+). Enforcement of this requirement is dependent on Spork 23 being enabled

70218+

Have a protocol version => MIN_MASTERNODE_PROTO_VERSION. During updates where this version is increased, masternodes will begin receiving PoSe score increases once > 80% of masternodes have upgrade (Dash Core 0.16.0+). Enforcement of this requirement is dependent on Spork 23 being enabled

Proof of Service Score Weighting#

The current PoSe scoring system is based only on participation in the LLMQ DKG process. This scoring system will expand over time to incorporate additional service requirements in support of the future Dash functionality.

Service

Percent of Score

Requirement

LLMQ DKG

100%

Participate in the DKG process used to establish LLMQs. Requires exchanging messages with other quorum members

PoSe Score Calculation#

As shown in the following table, the PoSe Score always decreases by 1 per block as long as a masternode has not been banned. Once banned, the masternode can only be restored by sending a Provider Update Service (ProUpServTx) special transaction.

PoSe Parameter

Value

Example Value

Maximum PoSe Score

Number of registered masternodes

5000

PoSe Score Increases

Maximum PoSe Score * 2/3

3333

PoSe Score Decreases

1 (per block)

Always 1

The current PoSe scoring algorithm increases the PoSe score by 66% of the maximum score for each failed DKG session. Depending on timing, this allows for no more than 2 failures for a masternode within a payment cycle (i.e a number of blocks equal to the number of registered masternodes).

For example, using the values from above with 5000 masternodes:

  • In the first 5000 block cycle, two DKG failures occur without the PoSe score exceeding the maximum. This happens since a sufficient number of blocks are mined prior to the second failure to drop the PoSe score below the threshold (< 5000 - 3333) that would result in banning.

  • In the second 5000 block cycle, the second DKG failure occurs too close to the first and results in the PoSe score exceeding the maximum limit. This results in the masternode receiving a PoSe Ban.

Payment Cycle

Block Number

Event

Score Change

PoSe Score

MN Status

1

1

DKG Failure (1)

+3333

3333

Valid

1

1734

1733 Blocks Mined

-1733

1600

Valid

1

1734

DKG Failure (2)

+3333

4933

Valid

1

5000

3266 Blocks Mined

-3266

1667

Valid

End of Payment Cycle 1

2

5500

500 Blocks Mined

-500

1167

Valid

2

5500

DKG Failure (3)

+3333

4500

Valid

2

7000

1500 Blocks Mined

-1500

3000

Valid

2

7000

DKG Failure (4)

+3333

6333

PoSe Banned

2

10000

End of Payment Cycle 2

-

6333

PoSe Banned