ABSTRACT
This chapter focuses on four blockchain-based Command-and-Control (C&C) mechanisms: ZombieCoin, Floating C&C Server, ChainChannels, and Unblockable Chains. It presents their system architectures and aims to evaluate the extraordinary features of these C&C mechanisms. Blockchain is a decentralized and distributed ledger technique. It contains a chain of inter-connected blocks that record a ledger of transactions. The ingenious creation of Bitcoin block structure makes itself an immutable and decentralized digital cryptocurrency, thus attracting developers to use Bitcoin as a tool for transforming current financial system. In Bitcoin transactions, a cryptocurrency holder needs to use private key to digitally sign transactions data and public key of Bitcoin receiver. ChainChannels proves that some infrastructures of blockchain such as digital signatures can also be used as C&C channels of botnets. For the past decade, attackers have been trying to build up a highly resistant and resilient botnet C&C infrastructures.
