Abstract
Underwater acoustic sensor networks (UASNs) are the most widely adopted technology for a wide range of underwater applications such as monitoring of climate change impacts, monitoring of oil and gas production facilities, pollution monitoring, and military surveillance applications. However, UASNs exhibit various challenges and limitations such as high ocean interference and noise, narrow bandwidth and low data rate, long link delay, dynamic network topology, sparse deployment due to high production cost, and limited powered sensor nodes. Due to these challenges, ensuring the security of the sensor nodes and networking protocols has become more challenging. In this article, we present the results of our comprehensive survey on the security of routing protocols in UASNs. First, various network and routing layer security threats and attacks are presented. Second, the existing countermeasures to various threats and attacks are summarized. Third, the existing attack-resilient routing protocol schemes are compared in terms of their capability to address security requirements and attacks, merits and limitations, mobility, and performance metrics such as end-to-end delay, packet delivery ratio, energy consumption, and network lifetime. Finally, various recommendations and future directions are presented.