  The number of IoT devices in use is increasing rapidly and so is the number
of IoT applications. As in any new technology, the rapid development means
rapid increase in security threats and attack surfaces. IoT security has proven
to be challenging throughout the past few years. However, another challenging
task is to prevent IoT devices from becoming a tool used by malicious attackers
to break into other systems. In this paper, we present a conceptual design in
which IoT devices are used as tools in brute-force attacks to break encryption
keys of block ciphers. The proposed design shows that with adequate number of
IoT devices employed in the attack, the attack can succeed in breaking
large-key block ciphers.
