ABSTRACT
A considerable number of electronic transaction systems employ classic
approaches based on centralized trust mechanisms, not exploiting
the latest technological advances. Alternatively, the concept of
blockchain stands out, elaborated without the need for this centralized
trust, but rather dependent on securely chained technologies in which
the elements involved can conduct secure negotiations. Blockchain is
designed to address security and distributed system issues through the
use of encryption, algorithms, P2P networks, and consensus mechanisms.
This paper presents a Denial of Service (DoS) security analysis
of the more traditional Practical Byzantine Fault Tolerance (PBFT)
and Proof of Work (PoW) consensus mechanisms available on
Multichain and Ethereum solutions based on a private / consortium
blockchain scenario. We present our results of a controlled DoS
attack, revealing the importance and need for security-related
analysis of blockchain implementations of private / consortium
blockchains.