Special Issue on Cryptographic Currency and Blockchain Technology

Cryptographic currency, or cryptocurrency, is a digital currency that makes use of cryptography for security. Many of the recent cryptocurrency proposals are completely decentralized, meaning that they are not issued by any central authority and could, in principle, be immune to the central bank’s interferences. Cryptocurrencies have become an important topic recently, thanks partly to the excitement brought about by bitcoin. Over a thousand alternative cryptocurrencies with various properties have been deployed in practice. It is estimated that total market capitalization of cryptocurrencies exceeds 320 billion USD. At the core of this new advancement is a distributed consensus protocol known as blockchain, which acts as a public ledger to support these electronic transactions.
Many technical challenges arise with the rapid development of these new technologies. One focus is to study the security and privacy of these virtual currencies. Besides, there is also a need to balance the privacy and the regulatory requirements. We note that other challenges and opportunities exist when it is deployed together with other technology such as IoT, or smart city.
Companies and researchers from academia have recognized the potential of blockchain technology extend beyond payment systems. There is also a great interest in applying blockchain technology to other applications scenarios. For example, blockchain has been used relieve the burden of public key infrastructure, collaborative intrusion detection system, data sharing, electronic voting, crowdsensing, digital rights management.