cryptomoney & payment networks what’s next?db770cd7-a791-420f... · 7 tx/s 20 tx/s 65,000...
TRANSCRIPT
ETH Zurich – Distributed Computing Group
Roger Wattenhofer
Cryptomoney & Payment Networks
What’s Next?
Preamble
Digital Transformation
Trust in me!
Blockchain
Blockchain = Ledger
Transaction
Transaction
Transaction
Block
Blockchain
Blockchain
Transaction Inspection
Blockchain
A Blockchain is Replicated
Blockchain Variants
Permissionless / Open
Permissioned / Closed
Permissioned / Closed
Do You Need a Blockchain?
Multiple Participants?
No Blockchain(use database)
no
Multiple Participants?
Participants Known?
No Blockchain(use database)
Permissioned Blockchain
PermissionlessBlockchain
yes
no
no
yesBIM
Blockchain Dimensions
PersistenceP
riva
cyEnergy
The Seven Blockchain Dimensions
Throughput Comparison
7 tx/s 20 tx/s 65,000 tx/s
A Simpler Blockchain
“The problem of course is the payee
can't verify that one of the owners did
not double-spend the coin.”
“We need a system for participants to
agree on a single history of the order in
which [transactions] were received.”
no double-spending
=single order
=consensus
Double-Spending
Blockchains Solve Double-Spending Problem
What About Network Outages?
Without Consensus
Permissioned Blockchain
Needed: 4 out of 5 signatures
Permissioned Blockchain
Permissioned Blockchain
Point To All Transactions!
No Main Chain, No Total Order
BD+E
EG+H
D F
G K
F+HJ
J+KLAB+C
C M
Payment Networks
Permissioned Blockchain (Layer 1)
Payments in Network (Layer 2)
Lightning Network (Explorer)
Many Layer 2 Designs
Duplex
Lightning
Eltoo
Raiden
Perun
Pisa
Connext
Plasma
NoCust
…
Channels
Payment channels
Payment channels
Payment channels
Funding transaction
5 4
Payment channel
5 4
2 7
8 1
Payment Network
ETH Zurich – Distributed Computing Group
Roger Wattenhofer
Strategic Formation of Payment Networks
Centralized design
Decentralized design
Online algorithms
Offline algorithms
Game theory
How to build payment networks
Multi-party channels
How can I profit the
most?
?
? ?
?
Given a sequence of transactions...
?
?
?
? (A, B, 6)(B, D, 8)(A, C, 2)(D, A, 10)(E, C, 3)(B, D, 6)
?
? ?
?
Given a sequence of transactions...
?
?
?
? (A, B, 6)(B, D, 8)(A, C, 2)(D, A, 10)(E, C, 3)(B, D, 6)
● Choose edges● Choose capital assignments● Choose tx
Hubs are almost optimal!
What about the online case?
No competitive algorithm even for a single channel!
Centralized design
Decentralized design
Online algorithms
Offline algorithms
Game theory
How to build payment networks
The Trade-offs
Blockchain fee: open/close
channels
Reduce cost of transactions
Gain lightning fees to route transactions
Social optimum = tree
f↑
f↑
Summary
Persistence
Pri
vacy
Energy
Thank You!Questions & Comments?
Roger Wattenhofer, ETH Zurich, www.disco.ethz.ch
Ene, mene, eins, zwei, drei, Bitcoins bringemir herbei. Hash Hash.
@grauhut