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Helsinki University of Technology Military grade wireless ad hoc networks professor Hannu H. Kari Laboratory for Theoretical Computer Science Department of Computer Science and Engineering Helsinki University of Technology (HUT) Espoo, Finland Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 1/59 Helsinki University of Technology • • • • • • • • • • • • Agenda Internet Privacy Military and civilian networks Problem statement Requirements Security levels Current and new solutions Context Aware Management/Policy Manager (CAM/PM) Packet Level Authentication (PLA) Applications Performance Conclusions Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 2/59 Helsinki University of Technology Internet • Internet was designed to survive nuclear war S D Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 3/59 Helsinki University of Technology Internet • Packets can be rerouted quickly S D Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 4/59 Helsinki University of Technology Internet • ...but one mole can damage the routing S D Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 5/59 Helsinki University of Technology Internet • ... or fill network with garbage ... S D Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 6/59 Helsinki University of Technology Internet • ...or corrupt transmitted data S D Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 7/59 Helsinki University of Technology Internet • Problems are dramatically getting worse, when • • • • • • • wireless networks are used instead of wired links dynamic network infrastructure is used instead of static nodes are mobile enemy is hostile nodes may get compromised strict Quality of Service requirements are needed transmission channel has very limited capacity Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 8/59 Helsinki University of Technology Privacy • Definition of Privacy Privacy is the claim of individuals, groups, and institutions to determine for themselves, when, how, and to what extent information about them is communicated to others. Alan Westin 1967 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 9/59 Helsinki University of Technology 5 categories of privacy • Data privacy (content) • Identity privacy (source/destination) • Location privacy (place) • Time privacy (when) • Privacy of existence (does it exist) Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 10/59 Helsinki University of Technology Military and civilian networks • Military networks • Clearly hostile enemy, high casulty rate of nodes • Governmental/resque • No clear enemy always present • Civilian • Professional criminals, hackers, industrial espionage Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 11/59 Helsinki University of Technology • • • • • • • • • • • • Problems in military grade wireless ad hoc networks Hostile enemy Privacy Routing Security Quality of service Performance Compromised nodes Dynamicity Life time of nodes Reliability Costs Unequality of nodes Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 12/59 Operating model for open source research Helsinki University of Technology Customer needs Protocol analysis/ verification Protocol testing Protocol design and validation Military requirements Protocol specifications Protocol implementations Civilian requirements Reference implementations Open source code Standards Business opportunities Idea Military grade wireless ad hoc networks Companies Hannu H. Kari/HUT/CS/TCS Solutions Page 13/59 Helsinki University of Technology Communication • Modes of communication • Human-human • Human-computer • Computer-computer • What is communication? • Exchange/deliver of information • • • • • Fetch information Send information Send commands Delegation of rights Friend or Foe? Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 14/59 Helsinki University of Technology Problem statement • How to ensure • the privacy • of communication • in military grade • wireless • ad hoc networks Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 15/59 Helsinki University of Technology Problem statement • How to ensure • the privacy (data, indentity, location, time, existence) • of (reliable) communication • in military grade (hostile enemies, compromised nodes, high casulty rate) • wireless (eavesdropping, disturbance, unreliable links) • ad hoc networks (no static infrastructure, mobile nodes, dynamic routing) Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 16/59 Helsinki University of Technology Problem statement • When the above problem is solved in this most difficult environment, the solution can be scaled down into other environments • • • • Fixed networks Static networks Civilian networks ... Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 17/59 Helsinki University of Technology Military network requirements • Military environment is the most difficult for the mobile communication and mobility management • Hostile enemy • Radio power usage restrictions • battery, reveal location, time, and importance of the node • Trust models • Handling of compromised nodes • Quality of service control • Not all nodes or packets are equal • Need for robustness • Fault resilience, automatic repair after failure, redundant routes • Need for performance Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 18/59 Helsinki University of Technology Military network requirements • Design goal to handle: • Two fast moving mobile nodes communicating in a militarygrade network using partially ad hoc -formed wireless access networks • Properties • • • • • Ultra frequent mobility (10 times/s), multipath routing Mobility management is tightly coupled with security QoS provided with security Access control coupled with security Ad hoc network needs to have security and mobility combined to route data packets • Ad hoc network provides connection to fixed network Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 19/59 Helsinki University of Technology • • Civilian networks What military networks are missing? In governmental and civilian networks we have • Cost issue • Protocols and equipment may not be too expensive • No black/white relation between nodes • Not just friend/foe separation • Own/allies/neutral/enemy • Limited radio spectrum • Commercial radio licences • No predefined trust between nodes • In military trust is easy to establish but difficult to keep • In commercial networks trust is difficult to establish but easy to keep Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 20/59 Helsinki University of Technology 3 levels of security Content/Information Secured communication layer (IPsec, TLS/SSL, Secure Shell, ...) Communication network Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 21/59 Helsinki University of Technology Current solutions • Application level security • PGP, Secure Shell, ... • Network level security • IPsec • Link level Security • WEP, A5,... Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 22/59 Helsinki University of Technology New solution • Context Aware Management/Policy Manager • Each node (computer) has a rule based policy manager that controls the behavior of the node and adapts it to environment changes • Adaptive trust model • Trust on nodes is not static but changes on time • Packet level authentication • A mechanism to ensure that only correct and authentic packets are timely processed Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 23/59 Context Aware Management/ Policy Manager Helsinki University of Technology Policy manager Application Mobility, security, QoS, access control, multicast layer Ad hoc networking layer Context aware management layer Local database IP Packet level authentication Access technology 1 Access technology 2 Military grade wireless ad hoc networks … Access technology N Hannu H. Kari/HUT/CS/TCS Page 24/59 Helsinki University of Technology Context Aware Management/ Policy Manager • Context Aware Management layer • Interfaces with all protocol layers and applications • Policy Manager • • • • Decisions are based on policy rules Collects information from all protocol layers and applications May have local user interface Can negotiate with neighboring PMs or take commands from remote entity • Policy rules • Formal representation of decision methodology • New rules can be sent by authorized entity (e.g., owner of the node, civil/military authority) Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 25/59 Helsinki University of Technology Trust • What is trust? • Belief that other party acts as agreed • Form of trust • Trust on • Indentity • Information • Timeliness • Transitivity of trust • Concept of incomplete trust Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 26/59 Helsinki University of Technology Packet level authentication • Analogy: • Security measures on notes • • • • • Holograms Microprint Watermarks UV-light ... • Receiver of notes can verify the authenticity of each note without consultation with banks or other authorities Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 27/59 Helsinki University of Technology Packet level authentication • How about IP world? • Each IP packet should have similar security measures • Receiver of a packet must be capable of verifying the authenticity of the IP packet without prior security association with the sender • Just like with notes, each IP packet shall have all necessary information to verify authenticity • In addition, • Since IP packets can be easily copied, we must have a mechanism to detect duplicated and delayed packets Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 28/59 Helsinki University of Technology Packet level authentication • General requirements • Security mechanism shall be based on public algorithms • No security by obscurity! • Public key algorithms and digital signatures provide undeniable proof of the origin • Symmetric keys can’t be used since nodes may be compromised • Protocol must be compatible with standard IP routers and applications • Standard header extensions shall be used • Solution must be robust and scaleable • It shall be applicable both in military and civilian networks Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 29/59 Helsinki University of Technology Packet level authentication • Why not IPsec? • Benefits of IPsec • Fast cryptoalgorithms and packet signatures due to symmetric keys • Well tested implementations and protocols • Disadvantages of IPsec • Can’t handle compromised nodes • IPsec is end-to-end protocol, intermediate nodes can’t validate packets • Requires several messages to establish security association between nodes • Scales badly to very dynamic networks Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 30/59 Helsinki University of Technology Packet level authentication • Basic operating principles • Sender digitally signs every packet • Extra header contains enough information for the receiver to check the packet authenticity • Header is handled the same way as MobileIP -header • A chain of trust can be used • Authenticity of every packet must be verified before using it • Impacts of hostile nodes shall be minimized, especially in the radio network • Decisions can be based on the trust level of the information and/or sending node Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 31/59 Helsinki University of Technology • Benefits • • • • • • • Packet level authentication Strong access control Only right packets are routed Easy to implement in HW (”Secure-CRC”) Less packets in the network Can be combined with QoS, AAA, firewalls, ... Secures all routing protocols Disadvantages • Increased packet size (~100 bytes) • transmission overhead, processing delays • Requires strong crypto algorithms • Elliptic curves, digital signatures, ... • More computation per packet • One or two digital signatures, one or two hashes per packet Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 32/59 Packet level authentication: Implementation Helsinki University of Technology IP packet IP HDR IP HDR TTP Military grade wireless ad hoc networks Pub-Key TTP-sig Seq # Hannu H. Kari/HUT/CS/TCS Packet-sig Page 33/59 Helsinki University of Technology • Packet level authentication: Implementation Extra header per packet 1. Authority • 2. Public key of sender • 3. Authority’s assurance that the sender’s key is valid Sending time (+sequence number) • 5. E.g., Elliptic curve (ECC) Authority’s signature of sender key and validity time • 4. General, TTP, Access-network operator, home operator,... Possibility to remove duplicates and old packets Signature of the sender of this packet • Sender’s assurance that he has sent this packet Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 34/59 Helsinki University of Technology • Packet level authentication: Implementation Sending: 1. Authority • 2. Public key of sender • 3. Constant field Sending time (+sequnce number) • 5. Constant field Authority’s signature of sender key and validity time • 4. Constant field Update per packet Signature of the sender of this packet • Caclulate per packet Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 35/59 Helsinki University of Technology • Packet level authentication: Implementation Reception, 1. packet: 1. Check sending time • 2. Authority • 3. Check validity Signature of the sender of this packet • 6. Store this Authority’s signature of sender key and validity time • 5. Verify that you know the authority (or ask your authority is this trustworthy) Public key of sender • 4. Check time Verify Sequence number • Store sequence number Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 36/59 Helsinki University of Technology • Packet level authentication: Implementation Reception, next packets: 1. Sending time • 2. Authority • 3. Verify data in cache Signature of the sender of this packet • 6. Verify data in cache Authority’s signature of sender key and validity time • 5. Verify data in cache Public key of sender • 4. Verify time and sequence numbers Verify Store time and sequence number Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 37/59 Helsinki University of Technology Packet level authentication: Implementation • Routers in the network • To authenticate a packet, we need a trust on the authority that has authorized the sender • directly (same authority as ours) • indirectly (a chain of trust) • Routers may operate memoryless • • • • no need for cache memory needs more computing power saves memory possibility to optimize Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 38/59 Helsinki University of Technology • • • • • • • • • Applications for PLA Securing wireless ad hoc networks Restricting DoS and DDoS attacks Reestablishing core network after military strike Handling compromised nodes Delegation of command chain ... Handling access control Replacing firewalls Handle charging/accounting Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 39/59 Helsinki University of Technology Application: Quick secured communication in battle field A A->B B B->A Any communication C learns that both A and B are from same group C A learns that C is from same group A First message from C to A C->A (message encrypted with A’s public key) C Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 40/59 Helsinki University of Technology Application: Restricting DoS attack D S ignore duplicates Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 41/59 Helsinki University of Technology Application: New core network: Military strike access network level core network level server level Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 42/59 Helsinki University of Technology Application: New core network: Reconfiguration New rules access network level core network level server level Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 43/59 Helsinki University of Technology Application: New core network: After military strike access network level core network level server level Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 44/59 Helsinki University of Technology Application: Excluding compromised nodes E1 detection of misbehavior E2 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 45/59 Helsinki University of Technology Application: Excluding compromised nodes E1 Nodes E1, E2 compromised E2 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 46/59 Helsinki University of Technology Application: Excluding compromised nodes E1 E2 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 47/59 Helsinki University of Technology Application: Delegation of command chain ”Trust G2” G1 Military grade wireless ad hoc networks G2 Hannu H. Kari/HUT/CS/TCS Page 48/59 Helsinki University of Technology Application: Delegation of command chain Authorization G2 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 49/59 Helsinki University of Technology Military grade wireless ad hoc networks Application: Delegation of command chain Hannu H. Kari/HUT/CS/TCS Page 50/59 Helsinki University of Technology Application: Revocation of large quantity of nodes Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 51/59 Helsinki University of Technology G1 Application: Revocation of large quantity of nodes ”Nodes E1, E2, ... compromised” ”New rules to nodes E1, E2, ...” Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 52/59 Helsinki University of Technology Application: Revocation of large quantity of nodes Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 53/59 Helsinki University of Technology • Sending node • • One digital signature per packet Verifying node/Receiving node • First packet: • • One certificate validation & One digital signature verification Next packets: • • Performance One digital signature verification per packet Digital signature requires one hash and one elliptic curve operatation Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 54/59 Helsinki University of Technology Performance • Elliptic curve HW implementation at ECE department of HUT • • • • FPGA with 350 000 gates Clock speed 66MHz 167 bit ECC multiplication on 100 µs using 167 bit arithmetics one signature in less than 1 ms • Performace is thus (in order of magnitude) • 1000 packets/s • With 500 Byte packet size, 4 Mbps Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 55/59 Helsinki University of Technology Performance • How about scaling up? • Pentium IV class silicon • Clock speed • 66MHz -> 3 GHz • (speedup factor 45) 350kG 66MHz 55MG 3GHz • Dice size • 350 000 gates -> 55 M gates • (160 parallel signature units) 1 Cnew Gnew 1 3GHz 55 000 000 × × = × × = 7.14 Msignature / s 1ms Cref Gref 1ms 66 Mhz 350 000 Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 56/59 Helsinki University of Technology Performance • Throughput of ”Pentium IV-class” PLA HW accelerator Throughput [Gbps] Signatures Packet size validated per packet 150B 500B One (*) 8.6 Two (**) 4.3 1500B 28.6 14.3 85.7 42.9 (**) For the first packet from a given sender (*) For the subsequent packets from the same sender Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 57/59 Methods to improve performance Helsinki University of Technology • • Parallel HW (multiple chips) Sending node • Include PLA only in every Nth packet ⇒ Potential security problem • Include forward credentials in PLA field • ”I’m going to send X packets in next Y seconds” • Receiving/Verifying node • Check packets randomly • Check only every Nth packet • Checking can be adaptive • • • • Check fewer packets from trusted nodes Check more packets at the beginning of the stream of packets More packets from same node of a flow, fewer checks done When you feel paranoid, check more Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 58/59 Helsinki University of Technology Conclusions • Context Aware Management/Policy Manager (CAM/PM) -architecture is rule based system that adapts node’s behavior according to its surrounding • Concept of incomplete trust allows us to handle trust levels other than 0 and 100% • Packet level authentication (PLA) provides scalable method to eliminate most of the faulty, forged, duplicated, and otherwise unwanted packets Military grade wireless ad hoc networks Hannu H. Kari/HUT/CS/TCS Page 59/59