中文摘要：

利用冗余复制技术，BQS（Byzantine quorum system）系统在异步信道上提供了能容忍f台服务器拜占庭失效的存储服务．COCA系统和CODEX系统设计了一种结合门限签名方案和BQS系统的服务器协议，完成了TSS-BQS（threshold signature schemes-BQS）系统与普通BQS系统相比，具有更易于支持Proactive Recovery,简化客户端密钥管理和客户端通信的优点．基于相同的系统模型和信道假设，提出了一种新的服务器协议，满足TSS-BQS系统的安全要求；而且与已有协议相比，该协议只需更少的通信轮数，在读／写并发情况下执行效果更优．

英文摘要：

Byzantine quorum systems （BQSs） provide attack-resilient storage services over asynchronous channels and tolerate f servers＇ Byzantine failures. COCA （Cornell online certification authority） and CODEX （COrnell Data EXchange） have designed a server protocol to implement BQSs threshold signature schemes （TSS-BQSs）, which can execute proactive recovery, conveniently, and can simplify the key management and communication of clients. Under the same system model and channel assumptions, a new server protocol that satisfies the security requirements of TSS-BQS is proposed. The proposed protocol involves less rounds of communication and performs better than that of COCA/CODEX in the case of concurrent read-write operations.