Hyunsung Kim

Dept. of Cyber Security, Kyungil University

Korea

Non-interactive Hierarchical Key Agreement Protocol over WHMS

Sensor NetworkSensor node

SensingProcessingCommunication

229

Sensor Network (Limitations)

Modest processing power – 8 MHz Very little storage – a few hundred

kilobits Short communication range –

consumes a lot of power Small form factor – several mm3

Minimal energy – constrains protocols Batteries have a finite lifetime Passive devices provide little energy

329

Sensor Network (Example)

429

Sensor Network (Example)

529

Sensor Network (Example)

629

729

Index

Aging SocietyWireless Health Monitoring SystemsWHMS Security ConcernsWHMS Privacy IssuesNon-Interactive Hierarchical Key Agreement ProtocolConclusion

Aging Society

829

Aging Society

929

Aging Society

1029

Wireless Health Monitoring Systems (WHMSs)

The integration of IT technology into traditional medicineDiagnosis, monitoring and treatment of illness at remoteIt can help individuals to improve their personal health and wellbeing

1129

WHMS System Configuration

1229

Internet

Physician, PHi

uHealth Server, SV

EHR

Patient PAi

GWi

SNi1 SNi2

SNi3

SNi4

SNi5

SNi6 Access point

Tier 1 Tier 2 Tier 3data generation data transmission data storage and access

WHMS Security Concerns

Data Encryption: The data is encrypted so that it is not disclosed whilst in transitData Integrality: The recipient can be sure that the data has not been altered or changedAuthentication: It is an efficient method against impersonation attacksFreshness Protection: This prevents the attacker from replaying the old frames

1329

WHMS Privacy Issues

All communications are required to be encrypted to protect the user’s privacyIt is also necessary that, specific users should not be identified unless there is a needEducating general people to know privacy issues

1429

One round communication to setup a session key between two communication partiesNon-Interactive Hierarchical Key Agreement Protocol Non-interactive Hierarchical access control EHR security provision

Non-Interactive Hierarchical Key Agreement Protocol over WHMS

1529

NotationsSymbol Description

PAi Patient iPHi Attending physician i of PAi

SV u-Health serverGWi Gateway iSNi,j Sensor node j in the GWi

IDi Entity i’s identifierADi Amplified identity of IDi

(S1, S2, S3, S4) Private key set of PKG, SiZq*

SK Session key established between two entitiesri Random numberG1, G2 Cyclic groups of prime order qP A generator of G1

ê Bilinear map G1 G1 G2

H() One way hash function H : {0, 1}* G1*

EK(M) Symmetric key encryption of M by using a key K∙ Multiplication || Concatenation

1629

Bilinear Pairing

Definition 1: Let G is an additive group of prime order q and GT a multiplicative group of the same order. Let P denote a generator of G. An admissible pairing is a bilinear map ê : GGGT

Bilinear : given Q, R G and a, bZ*q, we

have ê(aQ, bR) = ê(Q, R)ab

Non-degenerate : ê(P, P)1GT

Computable : ê is efficiently computable

1729

Permission Hierarchy

1829

SV

PH1 PH2 PHi…

SN1,1,1

GW1,1

SN1,1,k

GW1,j GW2,1 GW2,j GWi,1 GWi,j………

… SN2,1,1SN2,1,k… SNi,j,1

SNi,j,k…… …

…

Tier

1T

ier 2

Tier

3

System Initialization

PKG initializes two cyclic groups, G1 and G2, of prime order q, a bilinear pairing ê: G1G1→G2 and a hash function H: {0, 1}* G1

*

PKG creates a private key set (S1, S2, S3, S4) for a WHMS

PKG computes ADSV=H(IDSV) and ADSV·S1

1929

Physician Registration

PHi SV

SV Checks the validity of IDPHi

Computes ADPHi =H(IDPHi) ADPHi ·S2

Issues a key pair (ADSV·S1, ADPHi ·S2, S3, S4) (ADSV, ADPHi)

2029

Physician, PHi

uHealth Server, SV

IDPHi

Hierarchical Key Setup

2129

SV

PH1

…

SN1,1,1

GW1,1

Tier

1T

ier 2

Tier

3

PHi

GWi,j

SNi,j,k

(ADSV·S1, S2, S3, S4)

(ADSV·S1, ADPH ·S2, S3, S4)1

(ADSV·S1, ADPH ·S2, S3, S4)i

…

…

Patient Registration

PAi SV

SV Checks the validity of IDPAi

Computes ADGWi,j =H(IDGWi,j), ADGWi,j ·S3 ADSNi,j,k=H(IDSNi,j,k), ADSNi,j,k ·S4

Issues a key pair (ADSV·S1, ADPHi·S2, ADGWi,j·S3, S4),(ADSV,ADPHi,ADGWi,j)(ADSV·S1, ADPHi·S2, ADGWi,j·S3, ADSNi,j,k·S4),(ADSV,ADPHi,ADGWi,j,ADSNi,j,k)

2229

uHealth Server, SV

Patient PAi

GWi

SNi1 SNi2

SNi3

SNi4

SNi5

SNi6

IDPAi

Hierarchical Key Setup

2329

SV

PH1

…

SN1,1,1

GW1,1

Tier

1T

ier 2

Tier

3

PHi

GWi,j

SNi,j,k

(ADSV·S1, S2, S3, S4)

(ADSV·S1, ADPH ·S2, S3, S4)1

(ADSV·S1, ADPH ·S2, ADGW ·S3, S4)1 1,1

(ADSV·S1, ADPH ·S2, ADGW ·S3, ADSN ·S4)1 1,1 1,1,1

(ADSV·S1, ADPH ·S2, S3, S4)i

(ADSV·S1, ADPH ·S2, ADGW ·S3, S4)i i,j

(ADSV·S1, ADPH ·S2, ADGW ·S3, ADSN ·S4)i i,j i,j,k

…

…

Non-Interactive Key Agreement and Secure Communication

2429

Patient PAjPhysician, PHi

uHealth Server, SV

SNi,j,d

(ADSV·S1, ADPH ·S2, ADGW ·S3, ADSN ·S4)i i,j i,j,d

(ADSV, ADPH , ADGW , ADSN )i i,j i,j,d

(ADSV·S1, ADPH ·S2, S3, S4)i

(ADSV, ADPH )i

Chooses r1

Computes R1=r1·ADSNi,j,d

Computes SK1=ê(ADSV·S1, ADSV)· ê(ADPHi·S2, ADPHi)·ê(ADGWi,j·S3, ADPHi)· ê(ADSNi,j,d·S4 , ADPHi)r

1

Computes M1=ESK1(Datai)Computes MAC1=H(SK1||R1||M1)

{R1, M1, ADSNi,j,d, MAC1}

EHR

Non-Interactive Key Agreement and Secure Communication

2529

Patient PAj

Physician, PHi

EHR

SNi,j,d

(ADSV·S1, ADPH ·S2, ADGW ·S3, ADSN ·S4)i i,j i,j,d

(ADSV, ADPH , ADGW , ADSN )i i,j i,j,d

(ADSV·S1, ADPH ·S2, S3, S4)i

(ADSV, ADPH )i

Chooses r1

Computes R1=r1·ADSNi,j,d

Computes SK1=ê(ADSV·S1, ADSV)· ê(ADPHi·S2, ADPHi)·ê(ADGWi,j·S3, ADPHi)· ê(ADSNi,j,d·S4 , ADPHi)r1

Computes M1=ESK1(Datai)Computes MAC1=H(SK1||R1||M1) {R1, M1, ADSNi,j,d, MAC1}

Authenticated by SVComputes SK1’=ê(ADSV·S1, ADSV)· ê(ADPHi·S2, ADPHi)·ê(ADPHi, ADGWi,j)S

3· ê(ADPHi, R1)S

4

Verify MAC1?=H(SK1’||R1’||M1)Retrieve Datai=DSK1’(M1)

Session Key Equivalence

SK1=ê(ADSV·S1, ADSV)·ê(ADPHi·S2, ADPHi)· ê(ADGWi,j·S3, ADPHi)·ê(ADSNi,j,d·S4 , ADPHi)r

1

=ê(ADSV·S1, ADSV)·ê(ADPHi·S2, ADPHi)· ê(ADGWi,j·S3, ADPHi)·ê(ADSNi,j,d , ADPHi)r

1·S

4

= ê(ADSV·S1, ADSV)·ê(ADPHi·S2, ADPHi)· ê(ADGWi,j, ADPHi)S

3·ê(ADSNi,j,d , ADPHi)r1·S

4

= ê(ADSV·S1, ADSV)·ê(ADPHi·S2, ADPHi)· ê(ADGWi,j, ADPHi)S

3·ê(R1, ADPHi)S4

= ê(ADSV·S1, ADSV)·ê(ADPHi·S2, ADPHi)· ê(ADPHi, ADGWi,j)S

3·ê(ADPHi, R1)S4

=SK1’

2629

Non-Interactive Key Agreement and Secure Communication

2729

Internet

Patient PAi Physician, PHi

uHealth Server, SV

EHR

GWi

SNi1 SNi2

SNi3

SNi4

SNi5

SNi6 Access point

Tier 1 Tier 2 Tier 3data generation data transmission data storage and access

SNi4 GWi

PHi

SV

EHR

2829

Conclusion

Importance of Security and Privacy in Wireless Health Monitoring SystemNon-Interactive Hierarchical Key Agreement Protocol One round key establishment Hierarchical access control EHR security provision

Thank You !