I. INTRODUCTIONWireless sensor network consists of highly distributed autonomous sensor nodes to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion, or pollutants, and to cooperatively transmit their data across the network to a receiver ( destination) [1] [7]. A sensor node consists of a radio transceiver with an internal antenna or connected to an external antenna, a microcontroller and electronic circuits for interfacing with the sensors and an energy source such as battery[1][7].A. Topologies:The topologies used in wireless sensor network are Mesh, Star, Ring, Tree and Bus, Fully connected.Mesh Network.B. Features: • Power consumption constraints for nodes using batteries or energy harvesting • Ability to cope with node failures • Node mobility • Communication failures • Node heterogeneity • Scalability at large deployment scalesC. Application: • Military applications. • Environmental applications. • Healthcare applications. • Home and other commercial applications. Military Applications: • Monitoring of friendly forces, equipment and munitions • Reconnaissance of adversaries and terrain • Battlefield surveillance and battle damage assessment • Detection of nuclear, biological and chemical attacks Example: Area monitoring: the network nodes of wireless sensors are deployed in a particular area to detect the performance of an area. Environmental Applications: • Forest fire detection • Mapping the biocomplexity of the environment • Flood detection Example: Forest fires Detection: WSN nodes are deployed in the forest whenever a fire occurs in the forest, they detect the fire and control the fire in the forest. Air Pollution Monitoring: To monitor polluting gases in the atmosphere in...... middle of paper.. ....asymmetric encryption mechanism means that the sender and recipient share a secret key to encrypt and decrypt the message. AES is a better algorithm in symmetric encryption. Asymmetric encryption: Asymmetric encryption techniques mean that the sender has a public key but the recipient needs a private key to access the encryption key. Elliptic curve cryptography is a better technique. Hybrid Cryptographic Techniques for Security Against Wireless Sensor Network: Hybrid cryptographic techniques include symmetric and asymmetric encryption algorithms such as AES is a better symmetric encryption technique and ECC (elliptic curve cryptography) is a better asymmetric cryptography technique for WSN. VIII.CONCLUSIONHybrid encryption technique used to encrypt data on the network and other security techniques to protect the network from cyberattacks net. The network can be secure