yanchao zhang, yuguang fang wireless networks 2006.6 mmc lab. 임동혁

Yanchao Zhang, Yuguang FangWireless Networks

2006.6

MMC Lab. 임동혁

Introduction Network architecture and system

models Entity authentication Incontestable billing of mobile users System Analysis Conclusions

Large-scale WMNAuthenticationBilling

Conventional solutionHome-foreign-domain Drawback

Time-consuming, expensive execution authentication

Bilateral service level agreement(SLA) No consideration about how to reward

intermediate users for packet forwarding

UPASSNo need SLA between WMN operatorsAuthentication

ID-based cryptography(IBC)User vs serving WMNUser vs user in the same WMN

Certificate-based cryptography(CBC)Universal verifiability of passes

Billing Digital signature & one-way hash-chain Realtime micropayment approach

AssumptionsMesh router sends packets in one hop to all

users in its coverageA mobile user transmits packets multiple

hops to a mesh routerAll communications pass through a mesh

router

User-broker-operator relationship model

Broker

WMNOperato

r

User

Universal

pass

Universal

pass

Network

service

Network

service

payment

payment

usage data

usage data

Trust modelCBC for certification of trust-domain

parameter IBC in each trust domain

Trust domain setupTrust-domain parameter

(Hash function, domain-public-key, …) Certification of

domain parameterDomain-params are used

as public key

Pass modelRouter

R-NAI : routerID@operater_domain R-pass : (R-NAI, expiry-date) R-key : kH1(R-pass) k : operator’s domain-master-secret (R-pass, R-key): IBC public & private key pair

User U-NAI : userID@broker_domain U-pass : (U-NAI, expiry-date, otherTerms) U-key : kH1(U-pass) k : broker’s domain-master-secret (U-pass, U-key) : IBC public & private key pair

Pairwise shared keyUser-router authentication

Inter-domain authentication Intra-domain authentication

User-user authentication

Inter-domain authenticationU and R possesses each other’s authentic

domain-paramsProcedure

(1) (2) (3)

(4) (5) shared key :

Intra-domain authenticationBetween same WMN domainProcedure

(1) (2) (3)

Computationally efficient Fast hash instead of signature and encryption

User-user authenticationGet paid for his packet forwardingPairwise shared keys

Symmetric-key challenge-response authentication technique U1 send to U2 a challenge r1 encrypted KU1,U2

U2 report a correct response, (r1+1) U1 declares the authentication of U2 successful Similarly, U2 can authenticate U1

Billing basics Intermediate user compensation

Attaching to forwarded packet a message integrity code(MIC) calculated under its pairwise shared key with R1

R1 ascertain the user in forwarding packet for U1

Total payment (m-units per t-unit transmitted)

Payment structure

<am> : proof token <wi,t> : payment token Procedure

(1) U1R1, a1, (2) R1 checks MIC (3) saves

To use <wi+1,t> (1) U1R1, (2) R1 check (3) R1 checks MIC

Making paymentsU1 maintains a debt counter

R1 maintains a profit counter : maximum amount that user can owe : U1 make a payment

UserPayment format

(wi,j, j), where and

Micropayment (wi,j, j)

1 1U RDC

u j t

1

1 Rj u L

1 1

1U UDC DC j u L

1UDC

1UPC

1R

RouterStore payment token with highest index

(wi,k, k)

Receipt of (wi,j, j), R1 verifies j>k,

After verification, R1 replace (wi,k, k) with (wi,j, j) and

Intermediate usersR1 pay on behalf of U1

1 1U UPC PC j k L

Redemption of payment structureBroker VS R1

Payment record

Procedure

SecurityA user signs a payment structure digitallyPayment structure is both user-specific and

router-specific Low Computation

Rare public-key operationFast hash operation

Small Storage Communication

More efficient than home-foreign-domain model

UPASSFirst known secure authentication and

billing architecture for large-scale WMNsHomeless, no need for SLAsHybrid IBC/CBC trust modelLightweight realtime micropayment

approach