不稳定信道上的组播实时认证协议

在组播认证协议TESLA的基础上引入消息分散算法,提出一个全新的组播认证协议,它能够为不稳定信道上的组播通信提供实时认证。文章最后给出了该协议详细的性能分析。该文提出的组播认证协议是要为每个数据包增加60～80字节的认证信息就可以为很高丢包率(≈50%)的组播通信提供99%以上的实时认证率。协议还增加了系统的可扩展性,可以为分布更广、组员规模更大的组播应用提供安全认证。     

Covert data transmission mechanism based on dynamic label in blockchain

The existing blockchain data covert transmission scheme is faced with the problems of poor concealment, small channel capacity and low efficiency. This paper designs a new model for separating the data embedding mechanism from the transaction filtering mechanism, and proposes a new filtering algorithm based on the address dynamic label. In this scheme,the HMAC algorithm is used to construct the special address label, so that the receiving party can effectively screen the special transaction carrying the concealed information from the massive data in the blockchain ledger, and realize the concealed data transmission in the open blockchain scenario. Simulation results show that the proposed scheme can realize the hidden transmission of data in the real bitcoin network. The concealment and efficiency of the scheme are better than those of the traditional scheme.     

泥水分离机液压与气压控制系统

叙述了浙北某水利疏浚企业,针对落实泥水混合物堆积场地困难的实际情况,研发了一款新的液压与气压控制式泥水分离机。介绍了设备的结构形式、液压与气压控制系统、实际使用情况等,并提出了进一步优化完善此设计的建议。     

SCM: Secure and accountable TLS certificate management

In classical public‐key infrastructure (PKI), the certificate authorities (CAs) are fully trusted, and the security of the PKI relies on the trustworthiness of the CAs. However, recent failures and compromises of CAs showed that if a CA is corrupted, fake certificates may be issued, and the security of clients will be at risk. As emerging solutions, blockchain‐ and log‐based PKI proposals potentially solved the shortcomings of the PKI, in particular, eliminating the weakest link security and providing a rapid remedy to CAs' problems. Nevertheless, log‐based PKIs are still exposed to split‐world attacks if the attacker is capable of presenting two distinct signed versions of the log to the targeted victim(s), while the blockchain‐based PKIs have scaling and high‐cost issues to be overcome. To address these problems, this paper presents a secure and accountable transport layer security (TLS) certificate management (SCM), which is a next‐generation PKI framework. It combines the two emerging architectures, introducing novel mechanisms, and makes CAs and log servers accountable to domain owners. In SCM, CA‐signed domain certificates are stored in log servers, while the management of CAs and log servers is handed over to a group of domain owners, which is conducted on the blockchain platform. Different from existing blockchain‐based PKI proposals, SCM decreases the storage cost of blockchain from several hundreds of GB to only hundreds of megabytes. Finally, we analyze the security and performance of SCM and compare SCM with previous blockchain‐ and log‐based PKI schemes.     

New entity authentication and access control scheme in satellite communication network

With the increasing global demand for satellite communications,the problem of entity authentication and access control of the satellite communication network needs to be solved urgently.To solve this problem,a new multiple center-based entity authentication and cross-domain access control scheme was proposed.The scheme divided the multiple centers into two layers for entity authentication,and maped the authorization of the multiple domains to achieve access control.Simulation experiments show that the proposed scheme support the entity authentication for 100 million users.Furthermore,it also allows 1 million users to access in parallel.     

采用工艺强化措施提高S195型柴油机曲轴的疲劳强度

讨论Ｓ１９５型柴油机曲轴强度的薄弱环节－过渡圆角弯曲疲劳强度。介绍了几种工艺强化措施可大幅度提高疲劳强度,建议新设计的曲轴取较小的过渡圆角,使整机结构要紧凑。     

滚齿机液压系统的改进与应用

叙述了针对水利工程施工中所使用的设备,精度要求较低、且零部件非标多、损耗较快的特点,土法上马,研制了一台液压式简易滚齿机,进行自加工零件,取得了明显的综合实效.     

绢丝绞纱的染整工艺

根据绢丝绞纱的特点,精练条件应缓和,一般不需要预处理及常规的初,复练;染色的重点是防止色花,深浅和夹生等病疵,并提出了防止措施及生产中应注意的问题。     

Achieving adaptively secure data access control with privacy protection for lightweight IoT devices

The Internet of things (IoT) technology has been used in a wide range of fields,ranging from industrial manufacturing to daily lives.The IoT system contains num...