Nominated Proof-of-Stake

An efficient consensus

Take Back Web

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Role in Web

• Content/Service Provider
• Content/Service Consumer
• Infrastructure Provider

Benefit as Infra Provider

• Share security on chain
• Server location as you need

Join the Web

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Techical View

Technical Evolution

Consensus Network

• Multiple servers by different ownner → Network
• Work together → Consensus

Consensus

• One node at one slot

• PoW - By power of work competition
• PoS - By turn from nodes with Staking
• NPos - By turn from a small group

Problems

a small group but decentralized

Role in NPoS

• Validator
• Nominator
• Chill

One to Many

Easy, But Not  Fair

4 Validators

• Secure
  • Distribute to Fair
  • Total Maximize

Not Fair

Total: 40

Total: 40

Not Fair / Fair

9

9

6

6

10

10

9

9

14

14

6

6

Total: 30

Total: 40

Total: 37

Fair

Total: 40

Total: 37

Phragmen

1. Find validator
   • base on score (votes * staking value)
2. Redistribution the budget(votes * staking value)
   • balance on staking of validator and try to fair

Following not real equation
but it helps you to memorize

Example 

Winner:

Assignments:

Example 1

Winner:

Assignments:

• Validator view: 1:3
• Half Fair: 1:1.5
• Result:  1.5 : 1 (3:2)

Staking:1, 1000, 3000, 1, 1, 1000

Vote: (1), (2), (3), (1,2), (1,3), (2,3)

Example 2

Winner:  [(3, 5001), (2, 2001)]

Assignments:  [

(2, [(2, Perbill(1000000000))]),

(3, [(3, Perbill(1000000000))]),

(10, [(2, Perbill(1000000000))]),

(20, [(3, Perbill(1000000000))]),

(30, [(2, Perbill(666555575)), (3, Perbill(333444425))])]

Staking:1, 1000, 4000, 1, 1, 1000

Vote: (1), (2), (3), (1,2), (1,3), (2,3)

• Validator view: 1:4
• Half Fair : 1:2
• Result:  2 : 1 

Example 3

Winner:  [(3, 6001), (2, 2001)]

Assignments:  [

(2, [(2, Perbill(1000000000))]),

(3, [(3, Perbill(1000000000))]),

(10, [(2, Perbill(1000000000))]),

(20, [(3, Perbill(1000000000))]),

(30, [(2, Perbill(714183689)), (3, Perbill(285816311))])]

Staking:1, 1000, 5000, 1, 1, 1000

Vote: (1), (2), (3), (1,2), (1,3), (2,3)

• Validator view: 1:5
• Half Fair : 1:2.5
• Result:  2.5 : 1 

714183689/285816311 = 2.49875063638338

Example 4

Winner:  [(3, 7001), (2, 2001)]

Assignments:  [

(2, [(2, Perbill(1000000000))]),

(3, [(3, Perbill(1000000000))]),

(10, [(2, Perbill(1000000000))]),

(20, [(3, Perbill(1000000000))]),

(30, [(2, Perbill(749906262)), (3, Perbill(250093738))])]

Staking:1, 1000, 6000, 1, 1, 1000

Vote: (1), (2), (3), (1,2), (1,3), (2,3)

• Validator view: 1:6
• Half Fair : 1:3
• Be Fair:  3:1

Operation Details

Benefit & Duty

Validator

• Producing Blocks
• Bound Valuable
• Set benefit ratio
  • validator : nominator
• Slash when fail, then become chill

Nominator

• Chose the better Validators
• Bound Valuable
• Slash when validator fail

Darwinia

Dual Token Staking

Ring

• General valuable
• Bound 3 ~ 36 months to get Kton
• 10000 Ring 1 year → 1Kton
• Now & Future

Kton

• Long term valuable
• Pay for unbound penalty
• Past

Why we concern Past ?

Votes & Benefit

• Hard Threshold of Ring
  • White paper
• Rule of Benefit Distribution
  1. Half for Ring, Half for Kton
  2. Validator First
  3. Nominator After

Thanks for listening

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