2026-09-22T08:52:42Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/109360 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Viswanath, Pramod Wang, Xuechao 2021-03-05T21:36:57Z 2021-03-05T21:36:57Z 2020-11-16 2020-12 The Nakamoto longest chain protocol is remarkably simple and has been proven to provide security against any adversary with less than 50% of the total hashing power. Proof-of-stake (PoS) protocols are an energy-efficient alternative; however existing protocols adopting Nakamoto’s longest chain design achieve provable security only by allowing long-term predictability, subjecting the system to serious bribery attacks. In this thesis, we prove that a natural longest chain PoS protocol with predictability similar to that of Nakamoto’s PoW protocol can achieve security against any adversary with less than 1/(1 +e) fraction of the total stake. Moreover, we propose a new family of longest chain PoS protocols that achieve security against a 50% adversary, while only requiring short-term predictability. Our proofs present a new approach to analyzing the formal security of blockchains, based on a notion of Nakamoto block. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2021-03-04 without embargo terms The student, Xuechao Wang, accepted the attached license on 2020-11-13 at 15:05. The student, Xuechao Wang, submitted this Thesis for approval on 2020-11-13 at 15:22. This Thesis was approved for publication on 2020-11-16 at 12:02. DSpace SAF Submission Ingestion Package generated from Vireo submission #15884 on 2021-03-04 at 15:34:31 Made available in DSpace on 2021-03-05T21:36:57Z (GMT). No. of bitstreams: 2 WANG-THESIS-2020.pdf: 1107079 bytes, checksum: ebe22d2734d4a043a9dcc51ac9aab8b5 (MD5) LICENSE.txt: 4209 bytes, checksum: fa7565be4c4c129f0ce3da37d2c74abc (MD5) Previous issue date: 2020-11-16 application/pdf http://hdl.handle.net/2142/109360 en Copyright 2020 Xuechao Wang Blockchain Proof-of-stake Proof-of-stake longest chain protocols: security vs predicability text Thesis Electrical & Computer Eng Electrical & Computer Engr University of Illinois at Urbana-Champaign Thesis M.S.