Download presentation
Presentation is loading. Please wait.
Published byWilson Hardacre Modified over 10 years ago
1
Bitcoins Transaction Processing Yonatan Sompolinsky joint work with Aviv Zohar
2
Bitcoin hard to get easy to pass no authority, no money printing pseudonymous relatively secure ?high transaction volume decentralized cryptocurrency current protocol: conflict ghost protocol: in accord
3
Transactions in Bitcoin tx Bob Calvin ?irreversible tx
4
txs: block #81block #82 block #83 The Blockchain txs: ~ 10 min consistent grows in time kept locally at each node Time
5
A B2 B1 maintain one main chain only blocks discarded & txs cancelled Conflicting blockchains the longest chain rule delays => forks Time
6
Block tree vs Block chain 1 3 2 5 4 6 λ:= block creation rate = 6 per hour β:= growth rate of main chain = 4 per hour efficiency:= β/λ=4/6<1 Time delays => forks => inefficiency
7
Block size, Delay & Efficiency analysis of data provided to us by Decker and Wattenhofer λ = block creation rate β = growth rate of main chain 0.95 Block Propagation Time
8
Throughput (TPS) Transactions Processed per Second = (block size) X (growth rate of the main chain) 2000 1/600 TPS ~ 1736 TPS < 3.3 why?
9
Security - double spend attack tx Bob Calvin tx secret tx main chain publish !
10
Success of attack
11
Effect of increasing throughput efficiency security TPS delay
12
Security limitation on TPS attacker computational power (fraction) TPS Bitcoin today: secure but low throughput high TPS: more bandwidth needed secure TPS vulnerable TPS
13
Greedy Heaviest Observed Sub-Tree longest chain efficiency security
14
Greedy Heaviest Observed Sub-Tree B C1 A C2 C3 D1 D2 D3 E1 tx B tx main chain according to longest rule 10 4 5 1 1 1 2 6 main chain according to ghost Time
15
GHOST throughput no security constraint hardware constraints, e.g., network congestion, limit the feasible TPS 8.5-fold increase of current bandwidth can withstand TPS = 2000 in pipeline: improvement of ghost, same bandwidth more TPS … security high transaction volume
16
https://eprint.iacr.org/2013/881.pdf
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.