Security is a broadly used term encompassing the characteristics of authentication, integrity, privacy, non- repudiation, and anti-playback. In the case of our sensor network the security requirements are comprised of authentication, integrity, privacy (or confidentiality) and anti-playback. The recipient of a message needs to be able to be unequivocally assured that the message came from its stated source. Similarly, the recipient needs to be assured that the message was not altered in transit and that it is not an earlier message being re-played in order to veil the current environment. Finally, all communications need to be kept private so that eavesdroppers can- not intercept, study and.
