Securing Our Bluetooth Mobiles From Intruder Attack Using Enhanced Authentication Scheme And Plausible Exchange Algorithm

SECURING OUR BLUETO OTH MOBILES FROM INTRUDER ATTACK USING ENHANCED AUTHENTICAT ION SCHEME AND PLAUSIBLE EXCAHNGE ALGORITHM Ms.A.Rathika Ms. R.Sa ranya Ms.R.Iswarya Assistant Professor Final Year UG Student Fi nal Year UG Student VCET, Erode, India VCET, Erode, India VCET, Erode, India . ABSTRACT- When Bluetooth devices come within the range of another, an electronic convers ation takes place to determine wh ether the devices in ran ge are known or whether one needs to con trol the other. Most Bluetooth devices do not requ ire any form of user in teraction for this to occur. If devices within range are known to on e another, the devices automatically form a network- known as a pairing. Authentication addresses the identity of each communicating device. The sende r sends an encrypted authentication request frame to the receiver . The receiver sends an encrypted ch allenge frame ba ck to the sender. Both perform a predefined algorithm. The sender send s its findings back to the receive r, which in turn either allo ws or denies the connection. There are three different function s for authentication in Bluetooth-E1, E2, and E3. E1 is used when encrypti ng the authorization challenge-respons e values.E2 is for generating different link ke ys.E3 is used when creating the encryption key. Key words: link key, primitive root , challenge response scheme GENERALIZATION OF INITIALIZATION KEY: The creation of an initialization key is u sed when no other key s are present. The key is derived from a random num ber, a PIN, lengt h of the PIN and a uni t’s hardware address. The PIN code can either be a factory value o r the user can enter a maxim um of 16 octets. GENERALIZATION OF L INK KEY AND LINK KEY EXCHANGE: Whe n a link key is established between two units they will use that key for authentication. A link key is 128 bits long an d a shared betwee n two or more units, a new link key can be derived whe never to improve security. Each device creates a random no and encrypts it together with its h ardware address and produces initialization key.. AUTHENTICATIO N: The Bluetooth auth entication procedure is based on a challenge-response scheme. Two devi ces interacting in an authentication procedure a re referred to as the claimant and the ve rifier. The verifier is the blue tooth device valid ating the identity of another device. The claimant is the de vice attempting to prove its identity. The challenge-res ponse protocol val idates devices by verify ing the knowl edge of a secret key- a Bluetooth link k ey. The steps in the authenticatio n process are the followi ng: • Step1: the claim ant transmits its 48-bit address (BD_ADD) to the verifier. • Step2: the verifier transmits a 128-bit random challenge (AU_R AND) to the claimant. • Step3: the verifier uses the E 1 algorithm to compute an a uthentication resp onse using the address, link key and random challenge as inputs. • Step4: the cla imant returns the com puted response SRES, to t he verifier. (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 228 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 • Step5: t he verifier c o mpares the SRES from the claimant with the SRES t hat it computes. • Step 6: if the two 32-bit SRES values are equal, the verifier will continue connection establishment. .The E1 authent ication functi on used fo r the validation is b ased on the SAF ER+ algorithm. Fig1: Authentication Process PROBLEM IN THE CURRENT SYSTEM: Fig2: Message in Exis ting Authentication Process When the connect ion is made betwee n the Bluetoot h devices, an intruder de vice can be there in different ways. An intruder can act as the fake de vice in the different rol es. The fake device can beha ve as false slave or false master. Simila rly the intruder can be a active intruder or passive one. It can continue t he connections to t he both communi cating devices or detach the one end m essages sent by i ntruder C is shown in Fi g.3. In the existing auth entication scheme of Blue tooth technology mutual authenticatio n is performed. First one devi ce sends the random number for authentication to the device second, Then the secon d device sends the response a nd sends another rand om number f or the verificat ion of fi rst device. Then the first device sends t he response of random num ber send b sec ond device. I n this way the identification of both the d evices is done. In the above figure .2, de vice A sends a random number R1 t o device B for authent ication of de vice B. Then the device B sends the random number R2 and the device B sends t he ResR2 to device B Behavior of intruder C in ex isting scheme: Fig3:Message in Existin g Authentication Process by the intruder Suppose an intru der C wants t o make connection in between the b oth devices A a nd B. • Device A sen ds random nu mber R1 to the fake device B. • Fake de vice B now be haves as fake device B. • Now the device B sends the response Re s R1 to fake devi ce A. • Intruder’s C sends the authen tication random num ber R2 to fa ke device A. (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 229 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 • The intr uder C sends the ran dom number R 2 to device A. • The device A sends the Res R2 to fake device. • The fake device now se nds the same response Resr2 to device. Hence in this way the intrud er device makes the connection with the devices A and b. IMPROVED AUTHENTI CATION METHOD: In the authenticatio n scheme, mutual authentication is p erformed exclusively between master and slave. First, one is authenticated with the AU_RAND (chall enge) and SRES (resp onse) exchange. Then the other is Authenticated again using a challenge response mechani sm. We propose to ch ange this authentication message exchanges in a form such that first both parties exchange their authen tication random value and cl aimant does not sends its response before getting the res ponse from the verifier. In thi s method, the attacker cannot obtai n SRES vale from the other pa rty. Since the attacker acts as a verifier in both piconets, its authentication challenge is responded with ano ther authentication challenge from the genu ine entities. With the improved authen tication method, if messages exchanged in a nes ted form such that first both partie s exchange thei r random val ues and claimant does not sends its response from the verifie r. The messages are shown as below: Now there are two case in this au thentication procedure: ¾ When the request for connection is generated from the int ruder device C t o device A. ¾ When the req uest for conne ction is m ade from the device A t o device C. Case 1: request f rom c to A: In this case when the intruder C will initiate th e connection establishment pr ocedure with device A. • The fake de vice sends the ra ndom num ber R1 to device A. • The device A does not sen ds the response for R1. • It sends t he another random num ber R2 to fake device B for authent ication and wait s for the resp onse for R 2. S uppose the fake device is trying to get the response from device B. It sends the same random number to devices B. The device does not sends the response of R2,firstly it verifies the fake device A and sends the one another r andom num ber R3 waits fo r the response of R3 from fake de vice. Hence in this case the atta cker cant’ involve itself into the devices A and B. Case 2: Request from A to C: in this case when the request i s made from device A. The follo wing messages are exchanged bet ween the devices A, C and B (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 230 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 First the authent ication rando m number R1 is sent by device A. • The devi ce C sends the sam e random number R1 t o device B. • The devi ce C does not send the response o f R1,it sends the anot her random number R2 to fake de vice A for aut hentication. • The devi ce C transmits the random number R2 to device A and wai ts for the response of R2 from A. • The device A gives the response ‘ResR2’ of R2. • The device C gives theResR2 to device b. • The de vice B sends the ResR1in res ponse to the number R1 to device C. • The resR1 is sent as it is to device A by the device C. Hence the conn ectio n is made between the devices A and C and C and B, b ut this is o nly possible only wh en the request is initiated by the device A and simultaneously there is a connection between the de vice A and B. Integrity is maintained, but th e confidentiality is disturbe d. IMPLEMENTING MO RE SECURITY FOR RANDOM NU MBER EX CHANGE : The scheme im plemented in case 2 was insecure obvi ously. So by i mplement ing the encryption in key exchange we can have a new improved authenticated system with more security to avoid the above said intrud er attack. PLAUSIBLE EXCHANGE DIFFIE-HELLMA N KEY EXCHANGE: Device A select s a random num ber R1 such that R1 < P a prim e number whi ch is havi ng α as its primitive root and calculates S1= a R1 mod p. Sim ilarly device Selects R2 such that R 2 < p and calculates S2 = a R2 mod p. Each si de keeps the R value Private and S values Public. Device A computes K = S2 R1 mod p and B computes K = s1 R2 mod p s o the produce identical results. So even though the intruder knows the P, S and α value they can predict the S1 and S2 values. But they couldn’t predict th e original random number. Device A Fake B F ake A Intruder Device B R1 S 1 S 1 R 1 S 2 R 2 R2 S 2 Res R2 Res R1 PROCEDURE TO EXCHA NGE KEYS: Device A: S1= a R1 mod p Device B: S2 = a R2 mod p Device A: K =  s2 R1 mod p Device B: K = s1 R2 mod p (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 231 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 ADVANTAG ES: • This algorithm uses the discrete logarithmic function, which is an irreversible function and it can not be easily decrypted. • The secret inte gers S1 and S2 are discarded at the end of the session. T herefore, Diffie- Hellman key exchange by itself trivially achieves perfect forward sec recy because no long-term private keying material exists to be disclosed. CONCLUSI ONS: While Bluetooth has several nice features, it fails to be a secure replacement of wires. As we have shown that Bluetoo th is susceptible to the attack s by intruders independ ent of security mechanisms. If an unknown device wants to m ake connect ions or request for a service. The proper authentication is followed by authorization an d encryption, but authenticati on process shoul d be such that un known device woul d not get response of any ran dom number until and unless it will give response to the rando m number whi ch it wants t o make the connecti ons. If we give the pro vision that not any single slave will response until it verifies the identity o f other device and a nother m ethod is that one de vice can estimate the delay by observing the res ponse time given by the verifier, so in this way we an check the identity of the device and can improve the security. REFERENCES: [1] Inform ation Tec hnology Jou rnal Volum e5 Number 6, 2006 [2] Bluetoot h, s.i.g., 2001.spe cification of the bluetooth syste,core”, version 1.1. Availa ble at http://www.bluetooth.com/. [3] Jakobs on, M.and.W.sec urity,2001. weakness in Bluetooth a vailable at htt p://www.rsasec urity.com / [4] William Stalling s,3 rd edition Cryptography and Network Security/principles an d practices [5]http://www.cse.iitk.ac.in/users/braman/cs425/slide s/ security-overview. pdf [6] Cryptog raphy and net work security by Atul Kahate, 2003 ed ition [7] S.Bellovin and MMerritt,"Augumented Encrypted key Exchange: Password-Based P rotocols Secure against Dictionary Attacks," Proc. IEEE symp.Research in security and privacy [8]E.Bresson, O.Chevassut a nd D. Pointcheval,"Security Proofs for an Efficient password-base d key exchange," Proc. ACM C onf. Computer and Comm. Security, pp.241- 250,2003 [9] Appli ed Cryptogra phy and Net work securi ty : 7 th International Conference , ACNS 2009 , France, June 2009 Proceedin gs by Michel Abdalla , David Pointcheval Pierre-Alain Fouque Author’s profile Ms.A.Rathik a is now working as an Assistant professor at Velalar College of Engineering a nd Technolog y, Erode, Tamil Nadu. She has com pleted her ME at Anna University , Coimbatore and has more than six years of teaching experience. She has publishe d two papers in journals and al so presented m any papers in national and internation al conferences. Her field of interest is Network Security. Ms. R. Sara nya is current ly pursuin g her final year B.Tech IT programme in Velalar Co llege of Engineerin g and Technol ogy, Erode, Ta mil Nadu. She has present ed many pape rs in natio nal conference and technical sy m posium held at various colleges and universities and won laurels. She has more awareness on cryptogr aphy and network security which is her field of interest. (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 232 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 Ms. R. Iswary a is doing her fi nal year B.Tech IT programme in Velalar College of Engineering a nd Technolog y, Erode, Tami l Nadu. She has participated a nd presented many technical papers in nati onal level techni cal symposium and conferences and gained laurel s. Her area of interest is Ethical Hackin g and In formation Security. (IJCSIS) International Journal of Computer Science and Information Security, Vol. 7, No. 2, February 2010 233 http://sites.google.com/site/ijcsis/ ISSN 1947-5500