@article{zhou2002coca,
author = {Zhou, Lidong and Schneider, Fred B. and Renesse, Robbert Van},
title = {COCA: A Secure Distributed On-line Certification Authority},
year = {2002},
month = {November},
abstract = {COCA is a fault-tolerant and secure on-line certification authority that has been built and deployed both in a local area network and in the Internet. Extremely weak assumptions characterize environments in which COCA's protocols execute correctly: no assumption is made about execution speed and message delivery delays; channels are expected to exhibit only intermittent reliability; and with 3t + 1 COCA servers up to t may be faulty or compromised. COCA is the first system to integrate a Byzantine quorum system (used to achieve availability) with proactive recovery (used to defend against mobile adversaries which attack, compromise, and control one replica for a limited period of time before moving on to another). In addition to tackling problems associated with combining fault-tolerance and security, new proactive recovery protocols had to be developed. Experimental results give a quantitative evaluation for the cost and effectiveness of the protocols.},
publisher = {Association for Computing Machinery, Inc.},
url = {http://approjects.co.za/?big=en-us/research/publication/coca-a-secure-distributed-on-line-certification-authority/},
pages = {329-368},
journal = {Transactions on Computer Systems (TOCS)},
volume = {20},
edition = {Transactions on Computer Systems (TOCS)},
}