Providing Multi-layer Security Support for Wireless Communications across Multiple Trusted Domains

1. Wireless communication and cross-domain roaming • Each domain has unique network address and/or manages its security policies autonomously • Demand cross-domain mobility and security supports • Demand sound cryptographic design to resist security attacks • Demand efficient mechanisms for distributed security management • Unfortunately, link layer protocols provide limited mobility support and flawed security protection • No cross-domain mobility support • Insecurities in 802.11 WEP protocol • Vulnerabilities in link layer countermeasures: WEP2, 802.1X • Network layer security protocol IPsec provides qualitative protection to cross-domain wireless communications • Cross-domain mobility supports from mobile IP integration • Verified protocols from Internet VPN: AH, ESP • Distributed intra-domain security policy management • Sound cryptographic design • Encryption via standard cryptographic modes of operation • Keyed message authentication • Anti-replay mechanism • Appropriate key management Providing Multi-layer Security Support forWireless Communications across Multiple Trusted Domains Jiejun Kong, Mario Gerla, B. S. Prabhu, Rajit Gadh • Security design challenges • Collaborative link layer protection • Multi-layer integration • Distributed security management with efficient cross-domain support • Point-to-point Security Association (PPSA) and handoffs • Congenial security semantics allow us to define PPSA • Intra-layer security handoffs for mobility • Inter-layer security handoffs for multi-layer collaboration • A cross-domain security model based on DiffServ • Label-based security management • Extended Bell-La Padula model and inter-domain label translation Intra-domain Extended Bell-La Padula model:Allow connections between a low label server and a high label client • Prototype implementation • Entity authentication and key exchange:EAP-friendly protocols preferred, e.g., TLS/WTLS • Policy interpretation:KeyNote, SPSL, Prolog, Datalog • PPSA fields • Data_confidentiality_sa: encryption algorithm and key • Data_integrity_sa: data origin authentication algorithm and key • Host_security_info: mobile host’s addresses and label • Misc_security_info: anti-replay sequence number, PPSA expiration time • Network layer protection: IPsec AH, IPsec ESP • Link layer protection: WEP Both intra- and inter-domain managementcan be efficiently implemented Sample inter-domain label system translation (in KeyNote) Authorizer: "POLICY“# Licensees: # Licensee Compliance Value is _MAX_TRUST if missing altogetherComment: Convert a foreign domain's label system to local domain's label system# local domain _VALUES == “LABEL0,LABEL1,LABEL2,LABEL3”Conditions: @foreign_label == 0  "LABEL0"; (@foreign_label > 0 && @foreign_label < 10)  "LABEL1"; @foreign_label >= 10  "LABEL2";# LABEL3 is not allowed from the foreign domain to local domain