Public Blockchains Proof-of-Work Consortium & Private - - PowerPoint PPT Presentation

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Public Blockchains Proof-of-Work Consortium & Private - - PowerPoint PPT Presentation

Feb 03, 2023 10 likes •548 views

1200 700 The Attack of the Clones against Proof-of-Authority Parinya Ekparinya Vincent Gramoli Guillaume Jourjon Ekparinya et al, "The Attack of the Clones against PoA" Page 1 Public Blockchains Proof-of-Work Consortium &

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Ekparinya et al, "The Attack of the Clones against PoA" Page 1

The Attack of the Clones against Proof-of-Authority

Parinya Ekparinya Vincent Gramoli Guillaume Jourjon

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Ekparinya et al, "The Attack of the Clones against PoA" Page 2

Public Blockchains Proof-of-Work Consortium & Private Blockchains

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Ekparinya et al, "The Attack of the Clones against PoA" Page 3

Public Blockchains Proof-of-Work Consortium & Private Blockchains Proof-of-Authority

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Ekparinya et al, "The Attack of the Clones against PoA" Page 4

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Ekparinya et al, "The Attack of the Clones against PoA" Page 5

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Ekparinya et al, "The Attack of the Clones against PoA" Page 6

Why Proof-of-Authority (PoA)?

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Ekparinya et al, "The Attack of the Clones against PoA" Page 7

Why Proof-of-Authority (PoA)?

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Ekparinya et al, "The Attack of the Clones against PoA" Page 8

Why Proof-of-Authority (PoA)?

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Ekparinya et al, "The Attack of the Clones against PoA" Page 9

Why Proof-of-Authority (PoA)? BFT

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Ekparinya et al, "The Attack of the Clones against PoA" Page 10

Why Proof-of-Authority (PoA)? BFT

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Ekparinya et al, "The Attack of the Clones against PoA" Page 11

The Cloning Attack => Double-spending

$ 10 $ 10

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Ekparinya et al, "The Attack of the Clones against PoA" Page 12

The Cloning Attack => Double-spending

$ 10 $ 10

SAME TOKENS!!

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Ekparinya et al, "The Attack of the Clones against PoA" Page 13

Q: How is it possible to double spend on PoA/Ethereum?

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Ekparinya et al, "The Attack of the Clones against PoA" Page 14

N1 N2 N3 N4 N5 Sealers

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40 Decided

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

The Modus Operandi of AuRa

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N1 N2 N3 N4 N5 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

The Modus Operandi of AuRa

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N2 N3 N4 N5 N1 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

The Modus Operandi of AuRa

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N3 N4 N5 N1 N2 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

ZZz

The Modus Operandi of AuRa

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N4 N5 N1

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N2 N3 Sealers Blocks Time (s) 5 10 15 20 25 30 35 40

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Decided

The Modus Operandi of AuRa

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N3

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Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N4 N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75

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N5 N2 Group B Sealers Group B Blocks

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75 N4

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N2 Group B Sealers Group B Blocks

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N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75 N4 N5

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N2 Group B Sealers Group B Blocks

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N1

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75 N4 N5

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N2 Group B Sealers Group B Blocks

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N3 Group A Sealers Group A Blocks Time (s) 40 45 50 55 60 65 70 75 N4 N5

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N1

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Block decision duration network partition

– Since decision requires strictly more than half, only one partition may decide blocks Can decide a block

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Ekparinya et al, "The Attack of the Clones against PoA" Page 38

Block decision duration network partition

– Since decision requires strictly more than half, only one partition may decide blocks Can decide a block

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If one sealer become malicious

– A malicious sealer creates a clone to participate in both partitions!! – If n = 9, both partitions contain 5 sealers, therefore both may decide a block!! Can decide a block Can decide a block Malicious sealer Clone sealer

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The Cloning Attack

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The Cloning Attack

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The Cloning Attack

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The Cloning Attack

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The Cloning Attack

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Countermeasure

– The algorithm will be more resistant to the attack if it requires strictly more than two- thirds to decide a block as shown in the illustration below with n = 9 sealers. Cannot decide a block Cannot decide a block

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Key takeaways

– With the attack of the Clones, it is possible to double spend in PoA/Ethereum. – Provided sufficient network partition duration, the attacker can double spend with 100% success rate. – To promote safety property in PoA/Ethereum: the higher number of required sealers, the higher resistance against the attack. – The attack applies as well to Clique. The details can be found in paper. – We exchanged with the security experts of geth and parity. The developers of xDai have already took this attack into account in their POSDAO consensus algorithm.