Navigation signals should be steadily tracked to allow the extraction of navigation information, and support the calculation of navigation solution. Generally, extraction of navigation information is realized by GNSS tracking loops, which need to implement two critical operations: 1) tracking parameters should be precisely estimated in order to reliably decode the navigation message. 2) Successive tracking method of navigation information. This paper proposes a novel tracking framework using dynamic FLL assisting PLL strategy and a loop state detection monitor. The new framework extends traditional phase and delay locked loop (PLL/DLL) tracking framework, and contributions mainly lie in two parts. A dynamic framework for parameters adjustment is proposed to avoid tracking failure due to the change of environment, which is complemented in a FLL-PLL cooperative framework. Experimental results demonstrate the advantages of our algorithm compared with standard PLL/DLL framework. It is shown that the algorithm proposed is more suitable for tracking under signal attenuation situation, while maintaining high performance at the same time.

Random beacons play a crucial role in blockchains. Most random beacons in a blockchain are performed in a distributed approach to secure the generation of random numbers. However, blockchain nodes are in an open environment and are vulnerable to adversary reboot attacks. After such an attack, the number of members involved in a random number generation decreases. The random numbers generated by the system become insecure. To solve this problem while guaranteeing fast recovery of capabilities, we designed a threshold signature scheme based on share recovery. A bivariate polynomial was generated among the participants in the distributed key generation phase. While preserving the threshold signature key share, it can also help participants who lost their shares to recover. The same threshold setting for signing and recovery guarantees the security of the system. The results of our scheme show that we take an acceptable time overhead in distributed key generation and simultaneously enrich the share recovery functionality for the threshold signature-based random number generation scheme.

With the increasing demand for privacy protection in the blockchain, the universal zero-knowledge proof protocol has been developed and widely used. Because hash function is an important cryptographic primitive in a blockchain, the zero-knowledge proof of hash preimage has a wide range of application scenarios. However, it is hard to implement it due to the transformation of efficiency and execution complexity. Currently, there are only zero-knowledge proof circuits of some widely used hash functions that have been implemented, such as SHA256. SM3 is a Chinese hash function standard published by the Chinese Commercial Cryptography Administration Office for the use of electronic authentication service systems, and hence might be used in several cryptographic applications in China. As the national cryptographic hash function standard, the zero-knowledge proof circuit of SM3 (Chinese Commercial Cryptography) has not been implemented. Therefore, this paper analyzed the SM3 algorithm process, designed a new layered circuit structure, and implemented the SM3 hash preimage zero-knowledge proof circuit with a circuit size reduced by half compared to the automatic generator. Moreover, we proposed several extended practical protocols based on the SM3 zero-knowledge proof circuit, which is widely used in blockchain.