Optimized Denial-of-Service Threats on the Scalability of LT Coded Blockchains

Coded blockchains have acquired prominence in the recent past as a promising approach to slash the storage costs as well as to facilitate scalability. Within this class, Luby Transform (LT) coded blockchains are an appealing choice for scalability in heterogeneous networks owing to the availability of a wide range of low-complexity LT decoders. While these architectures have been studied from the aspects of storage savings and scalability, not much is known in terms of their security vulnerabilities. Pointing at this research gap, in this work, we present novel denial-of-service (DoS) threats on LT coded blockchains that target nodes with specific decoding capabilities, thereby preventing them from joining the network. Our proposed threats are non-oblivious in nature, wherein adversaries gain access to the archived blocks, and choose to execute their threat on a subset of them based on underlying coding scheme. We show that our optimized threats can achieve the same level of damage as that of blind attacks, however, with limited amount of resources. This is the first work of its kind that opens up new questions on designing coded blockchains to jointly provide storage savings, scalability and resilience to optimized threats.