2026-09-21T05:36:31Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/113214 2023-07-11 col_2142_5131 col_2142_10761 com_2142_5130 com_2142_10755 com_2142_234

DSpace SAF Submission Ingestion Package generated from Vireo submission #16997 on 2022-01-12 at 12:55:28 Made available in DSpace on 2022-01-12T22:35:19Z (GMT). No. of bitstreams: 3 AGARWALA-THESIS-2021.pdf: 852323 bytes, checksum: e4f93d6e3f2a33e14c9624b30d138f5d (MD5) Masters Thesis.zip: 1211729 bytes, checksum: 44855e987a9e016d77917fa08824f4f7 (MD5) LICENSE.txt: 4211 bytes, checksum: 0ac05d9265924e139e4651ed5a723515 (MD5) Previous issue date: 2021-07-19 Embargo set by: Seth Robbins for item 121140 Lift date: 2024-01-12T22:35:30Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only application/pdf Mohan, Sibin Agarwala, Disha 2022-01-12T22:35:19Z 2022-01-12T22:35:19Z 2024-01-12T22:35:30Z 2021-07-19 2021-08 Threshold cryptosystems eliminate a single point of failure by distributing the root of trust in applications like key management-as-a-service, signature schemes and encrypted data storage. However, existing threshold cryptosystems do not ensure availability when a malicious adversary corrupts more than half of the devices in the network. We present High Threshold Cryptosystem (HiTC), an iterative reboot-based framework for threshold cryptosystem that is resilient against a malicious mobile adversary that can corrupt up to all but one device in the network. With a careful design of rebooting devices, HiTC ensures that a sufficient number of honest devices are always available in the network to ensure that the system as a whole is always available. We also design a novel and efficient resharing protocol to protect secrets in the presence of a strong mobile adversary. We assess our security assumptions through case studies of real-world attacks and extensive measurements. We implement HiTC atop a distributed symmetric key encryption system and evaluate it using up to 18 AWS EC2 instances and up to 6 Raspberry Pis. Our evaluation using AWS EC2 instances demonstrates that HiTC is practical and incurs an average overhead of 20% over the baseline. Furthermore, the Raspberry pi setup performs poorly, but preliminary results prove that enhancement in implementation can help achieve better performance. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-08-01 The student, Disha Agarwala, accepted the attached license on 2021-07-16 at 20:18. The student, Disha Agarwala, submitted this Thesis for approval on 2021-07-16 at 20:55. This Thesis was approved for publication on 2021-07-19 at 15:30. http://hdl.handle.net/2142/113214 en Copyright 2021 Disha Agarwala High threshold cryptosystem Mobile adversaries Proactive Secret Sharing Security Reboot based framework for high-threshold cryptosystem text Thesis Computer Science Computer Science University of Illinois at Urbana-Champaign Thesis M.S.