When traditional signature algorithms such as blind signature and group signature applied to heterogeneous networks of blockchain, they might have problems like relying on trusted centers or low efficiency. Aiming at the problems, a threshold signature scheme suitable for blockchain electronic voting scenes was proposed. The proposed scheme was based on the Asmuth-Bloom secret sharing scheme and did not need a trusted center. Firstly, the signature was generated by the collaboration of blockchain nodes, implementing mutual verification between nodes and improving the node credibility. Secondly, a mechanism of nodes joining and exiting was established to adapt to the high mobility of the blockchain nodes. Finally, the node private keys were updated regularly to resist mobile attacks and make them forward-secure. Security analysis shows that the security of the scheme is based on the discrete logarithm problem, so that the scheme can effectively resist mobile attacks and is forward-secure. The performance analysis shows that compared with other schemes, this scheme has lower computational complexity in the signature generation and verification phases. The results show that the proposed scheme can be well applied to blockchain electronic voting scenes.

In terms of the problem that a safety-critical system will be paused, detected and resumed when security tools alert, and the delay between the occurrence and discovery of the false alarms (false positive or false negative) results in an effect on the availability of the guest Operating System (OS), a scheme based on virtualization was proposed. When a false alarm occurred, the operations of the suspicious application were quarantined correctly to avoid substantial system-wide damages. Then the operations of the suspicious application were logged and application inter-dependency information was generated according to its interactions with other applications. When the false alarm was determined, measures such as resuming the application's operations and killing the relevant applications according to the operation logs and inter-dependency information were taken so that the guest OS could reach the correct operating status quickly. The experimental results show that the scheme can reduce the overhead caused by rollback and recovery when a false alarm occurs. Compared to the situation without the proposed scheme, the overhead of handling the false alarm is reduced by 20%-50%. The proposed scheme can effectively reduce the effect of false alarm on the availability of clients, and can be applied in the cloud platform which provides services to safety-critical clients.