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Szu-Ying Chen2011.9.23

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3rd Generation Network

Universal Mobile Telecommunications System

Outline

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International Mobile Telecommunications for theyear 2000 (IMT-2000) specifications

1. Year 2000

2. 2GHz

3. 2Mbps

Proposed by International TelecommunicationUnion (ITU) in 1992

History

Standards

3rd Generation Networks

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Standards

CDMA2000

W-CDMA

TD-SCDMA

WiMAX

History

Standards

3rd Generation Networks

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Defined by the European TelecommunicationsStandards Institute (ETSI)

Developed the extremely successful 2nd generation GSMstandard

Evolved from the Global System for MobileCommunications (GSM)

Base on Wide band Code Division Multiple Access (W-CDMA)

Transferred to 3rd Generation Partnership Project

(3GPP) in 1998

History

Architecture

Components

Security

Universal Mobile Telecommunications System

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Architecture

Core Network (CN)

UMTS Terrestrial Radio Access Network (UTRAN)

User Equipment (UE)

History

Architecture

Components

Security

Universal Mobile Telecommunications System

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Components Serving Network (SN)

Visitor Location Register (VLR)

Home Environment (HE)

Access Network (AN)

Authentication Center (AuC)

International Mobile Equipment Identity number (IMEI)

International Mobile Subscriber Identity (IMSI)

Temporary Mobile Subscriber Identity (TMSI)

History

Architecture

Components

Security

Universal Mobile Telecommunications System

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Universal Subscriber Identity Module (USIM)

A secret key K shared with AuC

IMSI

TMSI

History

Architecture

Components

Security

Universal Mobile Telecommunications System

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Design Principles

1. UMTS security will build on the security of 2ndgeneration systems.

2. UMTS security will improve on the security of 2G

systems.3. UMTS security will offer new security features.

History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

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Security Features

1. Network access security

2. Network domain security

3. User domain security

4. Application domain security

5. Visibility and configuration of security

History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Security Features

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Comparison

GSM UMTS

Authentication Single Direction Bi-direction

Auth. Algorithm

A3, A8

(Not specified)

F1~F5

(MILEANAGE)

Encipher Key 64 bits 128 bits

Conf. AlgorithmA5

(Not published)F8

(KASUMI)

Integ. Algorithm -

F9

(KASUMI)

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Authentication and Key Agreement (AKA)

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Authentication and Key Agreement (AKA)1. MS request login/service of SN

2. SN demand MS to register

3. MS sends TMSI to SN

4. SN verifies the TMSI received from MS. If verification failed, ask

MS to send its IMSI5. MS sends IMSI to SN

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Authentication and Key Agreement (AKA)6. SN sends Auth Data Req Msg to HN

7. HN generates n ordered authentication vectors (AV)

8. HN sends AVs to SN

9. SN stores AVs to database and select on AV from them

10. SN sends User Auth Req Msg to MS including RAND(i) andAUTN(i)

11. MS verifies AUTN(i). If correct, MS computes RES(i), otherwise,

MS reject the connection.

12. MS sends User Auth Res Msg to SN including RES(i)

13. SN compares the XRES(i) stored in database with the receivedRES(i). If the values are equal, the authentication succeed. if not,the authentication failed.

14. After authentication succeed, MS could compute the value of CK,

IK with the pre-shared key K through algorithm f3, f4 for the

following communication.

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History

Architecture

Components

Security Principle

Feature

Comparison

Mechanism

Universal Mobile Telecommunications System

Authentication Vector

1. Message Authentication Code (MAC) f1( SQN, AMF,RAND, K )

2. eXpected RESponse (XRES) f2( K, RAND )

3. Cipher Key (CK) f3( K, RAND )

4. Integrity Key (IK) f4( K, RAND )

5. Anonymity Key (AK) - f5( K, RAND )

6. Authentication Token (AUTN) - SQN AK || AMF || MAC

AV(i) = RAND(i) || XRES(i) || CK(i) || IK(i) || AUTN(i)

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[1] UMTS Security Boman, K.; Horn, G.; Howard, P.; Niemi, V.;

Electronics & Communication Engineering Journal, 2002

[2] An Introduction to Access Security In UMTS

Koien, G.M.;

Wireless Communications, IEEE, 2004

[3] Securing a Wireless World

Yang, H.; Ricciato, F.; Lu, S.; Zhang, L.;

Proceedings of the IEEE ,2006

[4]

[5] Network and WiKipedia

Reference