Index Watchdog, 175 see also Mobile ad hoc networks (MANETs) Intrusion Detection Systems (IDSs), 162 acknowledgement-based, 184 agents, 182 classification of, 174 cluster-based, 180 collaborative, 184­186 cooperative, 180­182 defined, 173 dynamic hierarchical, 182­184 host-based, 174 mobile agent framework, 182 network-based, 174, 175 intrusion response, 177 invite replay billing attack, 774­776 IP address occupancy-based detection, 89 IP-occupancy reattack, 84­86 IPSec in defining VPNs, 714 single-trigger access, 618 syntax, 617 usability and performance evaluation, 625­627 verification of, 614­627 IPv4 basic security in mobility support for, 109 message origin authentication, 109­110 message replay protection, 111­112 mobility support in, 106­107 registration protocol with nonces, 112 registration protocol with timestamps, 111 security model, 109 IPv6 basic security in mobility support for, 112­113 care-of-test init procedure, 114 home test init procedure, 113 mobility support in, 107 return routability procedure, 112, 803 guarantees, 435 problems, 436­437 structure diversity, 437 key derivation hierarchy, 367 key distribution symmetric, 159­160 symmetric group, 160 key encryption keys (KEKs), 160 key management autonomous, 157­158 certificateless public, 158­159 composite, 157 fault tolerance, 153 self-organizing, 156 key predistribution, 160 key update, 160 k -grouping, 441 k -isomorphism technique, 437­438 k -neighborhood anonymity, 435 Kullback-Leibler (KL)-distance, 447 L labels, 577