Wireless sensor networks have been researched extensively over the past few years. They were first used by the military for surveillance purposes and have since expanded into industrial and civilian uses such as weather, pollution, traffic control, and healthcare. One aspect of wireless sensor networks on which research has been conducted is the security of wireless sensor networks. These networks are vulnerable to hackers who might go into the network with the intent of rendering it useless. An example of this would be an enemy commandeering a drone and getting it to attack friendly forces. In this paper, we review the security of wireless sensor networks. Areas that are covered include: architectures and routing protocols, security issues that include context and design as well as confidentiality, integrity, and authenticity, algorithms, and performance issues for wireless sensor network design. Performance of the Self-Originating Wireless Sensor Network (SOWSN), Practical Algorithm for Data Security (PADS), and mechanisms for in-network processing were investigated in further detail with SOWSN having the best performance as a result of it being based on realistic scenarios.