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CBC Mode and Initial Vector for the AES algorithm in WIMAX Protocol Stack

CBC Mode and Initial Vector for the AES algorithm in WIMAX Protocol Stack

JAN 2, 2012

AJALA.AJ

[email protected]

AJAL.A.J ASST PROF – METS SCHOOL OF ENGG , MALA; KERALA MOB: 0- 8907305642

OBJECTIVE

TO IMPLEMENT THE NETWORK LEVEL SECURITY IN IEEE-802.16e STANDARDS USING Advanced Encryption Standards [AES]

WIMAX

MOBILE WIMAXFIXED WIMAX


MOTIVATION ( SECURITY ISSUES )

CONFIDENTALITY

MESSAGE INTEGRITY

AUTHENTICATION

NON- REPUDATION


Review of the Block Cipher

Pseudo-random number

generator

Plaintext data byte p

“key stream” byte b

Ciphertext data byte c = p b


Encryption Algorithms

Unclassified use Suite B

Through2010

After2010

Secret Top Secret

AES

128

192

256

TDES

2key TDES

3key TDES


66

WiMAX Protocol Stack● Provides secure

communication Data encrypted with cipher

clock chaining mode of DES

● Prevents theft of service SSs authenticated by BS using

key management protocol

Authentication

7

Data Key Exchange

8

Data Encryption

9

WIMAX –

FEATURES

OFDM

Sub Channelization

Directional Antennas

Adaptive Modulation

System Architecture 2008

OFDMAOFDMA

System Architecture 2008 11

BS

User A

User B

User C

Spectrum

Frequency

User A

User B

User C

Frequency

TimeUser A

User B

User C

04/12/23

WiMAX Security Architecture

13

System Architecture

13

14

Subsystem design (Data Privacy Subsystem)

14

Security Suite Specification

It is based on 3 security mechanisms:

CBC-MAC mode, to provide for data authentication only

AES-CTR mode, to provide data confidentiality only

AES-CCM mode, to provide both data confidentiality and data authenticity.


CBC Mode

P1

IV

EK

C1

P2

EK

C2

C1

DK

P1

IV

C2

DK

P2

Pn

EK

Cn

Cn

DK

Pn

EN

CR

YP

TD

EC

RY

PT


Counter Mode(a stream cipher mode)

EN

CR

YP

TD

EC

RY

PT

C1

EK

CTR11

P1

P2

EK

C2

CTR2

C2

EK

P2

CTR2

Pn

EK

Cn

Cn

EK

Pn

CTRn

CTRn

• • •

• • •

P1

EK

C1

CTR1

Keystream


CCM Mode Overview

Designed for IEEE 802.11 wireless LANs

Use CBC-MAC to compute a MIC (Message Integrity Code) on the plaintext header, length of the header, and the payload

Use CTR mode to encrypt the payload— Counter values 1, 2, 3, …

Use CTR mode to encrypt the MIC — anywhere else we’d call it a MAC rather than a MIC

— Counter value 0

Header Payload MIC

Authenticated

Encrypted



BI-SOVA BLOCK DIAGRAM


TRACE BACK SYSTOLIC ARRAY OF BI-SOVA – SIMULATION RESULTS


SYSTOLIC ARRAYTimeunit

11

10

1000

0000

0100

1011

0000

1101

1101

0000

0000

00xx

01 10

1000

0000

0100

1011

0000

1101

1101

0000

0000

00xx

11

1110

9

0000

0100

1011

0000

1101

1101

0000

0000

00xx

SELE-CTIONUNIT

1SELE-CTIONUNIT

00XX

20

1111

0000

0000

1011

0001

1000

1101

0001

0100

1110

1000

0000

0100

1011

0000

1101

1101

0000

01 10 01 00 10 11 00 01 01 00 0

0000

.

.

19

11 00 10 01 01 10 00 10 10 00

0000

0000

1011

0001

1000

1101

0001

0100

1110

1000

0000

0100

1011

0000

1101

1101

0000

0000

00XX

SELE-CTIONUNIT

SELE-CTIONUNIT

SELE-CTIONUNIT

SELE-CTIONUNIT

.

.

A register containing Decision Vector

A register containing Smallest Path Metric


BI-SOVA SIMULATION RESULTS



TRANCEIVER OF MIMO OFDM

SUMMARY

Advanced Encryption standard comes under suite B achieves top level secret using CCM mode

Decoder part has been completely implemented sucessfully

FFT module has been analyzed to suite IEEE802.16e standards



REFERENCES[1] C. Thmas, M. A. Bickerstaff, L. M. Davis, T. Prokop, B. Widdup,

G. Zhou, D. Garrett, C. Nicol, “Integrated circuits for channel coding in 3G cellular mobile wireless systems,” IEEE Commun. Mag., vol. 41, no. 8, pp. 150-159, Aug. 2003.

[2] C.-S. Lee, T. Keller, and L. Hanzo, “OFDM-based turbo-coded hierarchical and non-hierarchical terrestrial mobile digital video broadcasting,” IEEE Trans. on Broadcasting, vol. 46, no. 1, pp. 1-

22, Mar. 2000.

[3] C.-H. Wang, W.-T. Wang, and C.-C. Chao, “A unified structure of trellis-based soft-output decoding algorithms for turbo codes,” IEEE Trans. on Commun., vol. 52, no. 8, pp. 1355-1366, Aug. 2004.

[4] L. Papke and P. Robertson, “Improved decoding with the SOVA in a parallel concatenated (turbo-code) scheme,” in Proc. ICC96, pp. 102-106.


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