Implementation of public key cryptography in kerberos with prevention 2


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Implementation of public key cryptography in kerberos with prevention 2

  1. 1. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME248IMPLEMENTATION OF PUBLIC KEY CRYPTOGRAPHY INKERBEROS WITH PREVENTION OF SECURITY ATTACKSEr. Abhijeet1, Mr. Praveen Tripathi2, Er.Anuja Priyam3, Er.Vivek kumar41M. Tech. Computer Science Student, Kanpur Institute of Technology Kanpur,2Assistant Professor Computer Science Student, Kanpur Institute of Technology Kanpur3M. Tech. Computer Science Student, Kanpur Institute of Technology Kanpur4M. Tech. Computer Science Student, Kanpur Institute of Technology KanpurABSTRACTUse of Public key cryptography is the limitation of Kerberos and by using symmetrickey cryptography there is some attacks, Replay attack and password attacks are serious issuesin the Kerberos authentication protocol. Public Key Cryptography for Initial Authentication(PKINIT) is the way of using public key cryptography in Kerberos but it is much time taking.Many ideas have been proposed to prevent these attacks but they increase complexity of thetotal Kerberos environment. In this Thesis we present an improved method which preventsreplay attacks and password attacks by using Public Key Cryptography (both RSA andDiffie-Hellman Key Exchange algorithm).Keyword: Kerberos, Password attack, public key cryptography, PKINIT, Replay attack,Authentication Server.1. INTRODUCTIONProviding security services to the user in a secure way is an issue. Attackers can easilygain information during its transmission across the network and then gain unauthorizedaccess to the servers, to whom they are not able to access. So, in this scenario, servers shouldbe able to authenticate all requests for services. Authentication is a way of ensuring that noone can access the system without providing the way that he has access right. Therefore,instead of each server check request for services, Kerberos provides a central server whichdoes the task of authentication. Security involves Implementation of measures to protectattacks.INTERNATIONAL JOURNAL OF COMPUTER ENGINEERING& TECHNOLOGY (IJCET)ISSN 0976 – 6367(Print)ISSN 0976 – 6375(Online)Volume 4, Issue 3, May-June (2013), pp. 248-253© IAEME: Impact Factor (2013): 6.1302 (Calculated by GISI)www.jifactor.comIJCET© I A E M E
  2. 2. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME249But it does not mean that an attack will never occur. For example, preventing anoutside attacks doesn’t’ mean that you are secure, attacks may occur from inside oforganization. Researchers have proved that many attacks occur from inside of theorganization. Therefore, it is necessary to provide security inside of an organization.Authentication protocol is one of the most classical single sign-on protocols. Authenticationis the base of secure network environment. Kerberos originated by MIT Project Athena [1]isone of the most widely-adopted authentication protocols. The overall scheme of Kerberos isthat of a trusted third party that uses a protocol based on that proposed by Needham andSchroeder [2].A single sign-on system means that a user can access all services from the applicationservers after only sign on one time in a multiple application systems. Kerberos V5 is beingused at present but there are lots of replay and password attack problems in it. Kerberos V5was designed to overcome some of the deficiencies of Kerberos V4, but it can’t guarantee toavoid replay and password attack.2. LITERATURE SURVEY2.1 OVERVIEW OF KERBEROS PROTOCOLKerberos [6] is the authentication protocol between a server and client through atrusted third party in an open network environment. Based on Needham and Schroeder’smodel, the Authentication server (AS), the trusted third party shares secret keys with allentities and authenticates the users with the secret keys. When a client requests authenticationfrom it, the server grants a ticket encrypted with a pairwise key between the server and theclient, and authenticates the client. The client authenticates itself with the Ticket GrantingServer (TGS) by delivering the ticket received from the AS. The TGS issues a ServiceGranting Ticket after authenticating the client for service, and the client requests a servicefrom the server by presenting this SGT. Finally, the server provides the service after verifyingthis SGT. Fig shows the processes of Kerberos.Adding public-key cryptography to Kerberos provides a nice congruence to public-key protocols, obviates the human users burden to manage strong passwords, and allowsKerberized applications to take advantage of existing key services and identity management.
  3. 3. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME2502.2 Replay and Password attacksMany schemes have been proposed to prevent replay attack in Kerberosauthentication protocol. Jian [2] proposed an optimized way to prevent password attack andreplay attack in single Signon system. Multiple databases were added to provide theauthentication and authorization in order to prevent replay attack. In this approach,Authentication Server sends Ticket-Granting-Ticket to user as well as to Ticket- Granting-Server (TGS).Similarly; TGS sends Service-Granting-Ticket to both Client and Applicationserver. TGS and Application server, each has their own database. They store these tickets intheir database and if attacker replays Ticket-Granting-Ticket (TGT) or Service-Granting-Ticket, they can easily detect whether this is an attack or not A dynamic double passwordbased sign-on protocol was proposed [3]. That protocol makes use of two passwords that areneeded during the user registration and log files concept was used. Log file contained thedetails when a particular user visited to a server which could be a authentication server,Ticket Granting Server or Application Server. Application server generates log file andforwards to authentication server even after responding the user. Authentication server passesthis log file to clients. Similarly, Authentication server also passes its log file. Therefore, auser can make a judgment on security of password through auditing log files and allowed tomodifying the password. So, if an attacker has captured a password, client can easily changeit by looking and analyzing at the log files.In [4], a concept is provided to prevent replay attack in Kerberos by using a freshnesswhich makes use of new Symbolic Model Verifier.Location based Kerberos authentication protocol is described in [5]. In this approachserver captures P(Y) code off all the client in the network and it assigns ticket granting ticketto the client by encrypting session key( used for communication between TGS and client) andTGT with the P(Y) code of user. After receiving this message, client accepts its P(Y) codeusing GPS and decrypts the message. So, if an attacker is able to capture the message, then hewill not be able to decrypt the message because P(Y) code length is in several of gigabits. Itwill result in the failure of the ticket due to time synchronization problems. Here, userphysical location is added as an additional message into the Kerberos protocol, which helpsto determine physical location of the message provider. Server sends (TGT) to client byencrypting session key with the hash value of user physical location. So, even if an attackercaptures a message, he will have to break two phase security to get session ticket and in thisprocess, ticket time may expire. Capturing user physical location and adding it as a newauthentication factor into the Kerberos Protocol method [7] was proposed to prevent replayattack. It used N-BAN logic (modified version of BAN logic [6]) to apply on the modifiedKerberos protocol.Benjamin [8] proposes a method for the inspection of replay attacks on Kerberosauthentication protocol in which the protocol was specified by using the Object-Z.Modified Symbolic Model verifier [9] approach was presented to find problems with respectto the replay attack.Some basic principles [10] were defined which are necessary to be used whiledesigning the cryptography protocols. Five different strategies are presented. By using thesestrategies it is possible to design cryptographic protocols which show robustness againstdifferent classes of replay attacks.A new protocol for key distribution was proposed [11] after analysing the securityflaws with different protocols that are currently used for the authentication as well as for keydistribution. This proposed model is based on using symmetric keys.
  4. 4. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME2512.3 PKINIT(Public Key Cryptography for Initial Authentication in Kerberos)[11]Pkinit provides support for using public-key authentication with Kerberos. Pkinit isuseful in the following situations:1. Using smart cards for Kerberos authentication2. Authentication based on soft tokens (or certificates stored on a computer) instead ofpasswords3. In conjunction with anonymous kerberos and FAST protecting password exchanges toremove the possibility of dictionary attacks.This article describes minimal Pkinit configuration for a KDC and clients. It assumes youalready have a Kerberos realm functioning and that you have the openssl command available.The following steps are involved:1. Setting up a certificate authority2. Generating a KDC certificate3. Generating client certificates4. Configuring the KDC and clients5. TestingPkinit requires a public key infrastructure. The simplest use of Pkinit (anonymous kerberos)requires a certificate authority (CA) certificate and a KDC certificate. The certificateauthority certificate is known by all clients; any certificates signed by this certificate aretrusted by the clients. The KDC certificate is signed by the certificate authority certificate(and thus trusted by the clients) and identifies the KDC.If Pkinit is used with smart cards or for other forms of user authentication, then each userwill need a certificate as well.3. PROPOSED ALGORITHMHere we are using a new way of implementing public key cryptography in Kerberos.There is an authentication server, a ticket granting server, a real server and many clientsregistered on AS server. Both AS(authentication server) and TGS(ticket grantingserver)maintain its database. AS database contains ID of all registered clients, correspondingpassword and public key. TGS database contains a set of prime numbers and correspondingprimitive roots and all real server with its password.The steps of algorithms is given below
  5. 5. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME252Where Ticket for TGS contain-(client id, client network address, ticket validity period, andclient/TGS session key Encrypted with KAS-TGS)Notations:C=Client.AS=Authentication Server.TGS= Ticket Granting Server.V=Real Server.E=Encryption.PRC=Private key of client.PU= PUBLIC KEY.IDC= ID OF CLIENT.IDTGS=ID OF TICKET GRANTING SERVER.KC-TGS=CLIENT-TGS SESSION KEY.KC-V=CLIENT-SERVER SHARED KEY.PSWDC=PASSWORD OF CLIENT.PSWDV=PASSWORD OF SERVER.4. CONCLUSIONSAfter using public key cryptography in this way we can prevent Kerberos fromsecurity attacks like password or reply attack. This is also a new way of Implementing PublicKey Cryptography in Kerberos.REFERENCES[1]Y. Kirsal, and O. Gemikonakli, “Further Improvements to the Kerberos TimedAuthentication Protocol,” International Conference on Telecommunications and Networking,University Bridgeport, Bridgeport, May 2007.[2]R. Needham, and M. Schroeder, “Using encryption for authentication in large networks ofcomputers,” Communications of the ACM, pp.993- 999, December 1978.[3]C. Neuman, S.Hartman and K. Raeburn, ” The Kerberos Network Authentication Service(V5),” July 2005 ,[4] Eric Cole, Ronald L. Krutz, James Conley, Brian Reisman, Mitch Ruebush, NetworksecurityFundamentals (John Wiley & Sons, ISBN 978-0-470-10192-6, 2008)[5] B. Clifford Neuman, Theodore Ts‘o, Kerberos: An Authentication Service for ComputerNetworks, IEEE Communications Magazine September 1994[6] B. C. Neuman and T. Ts’o, “Kerberos: an authentication service for computer networks,”IEEE Comm. Magn., vol.32, no.9, Sep. 2004.[6] Paul Syverson, A Taxonomy of Replay Attacks, IEEE 1994.[7] Yang Jian, An Improved Scheme of Single Sign-on Protocol, Fifth InternationalConference on Information Assurance and Security, PP. 495-498, IEEE 2009[8] Yang Jian, An Improved Scheme of Single Sign-on Protocol Based on Dynamic DoublePassword, International Conference on Environmental Science and Information ApplicationTechnology, IEEE 2009. PP. 572-575.[9] S. Adyanthaya, S. Rukmangada, A. Tiwari and S. Singh, Modeling Freshness Concept toovercome Replay Attack in Kerberos Protocol using NuSMV, International Conference onComputer & Communication Technology IEEE-2010
  6. 6. International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME253[10] Abdelmajid, N.T., Hossain M.A, Shepherd S, Mahmoud K, Location-Based KerberosAuthentication Protocol, IEEE International Conference on Social Computing / IEEEInternational Conference on Privacy, Security, Risk and Trust IEEE-2010[11] B. Tung, and L. Zhu, “Public Key Cryptography for Initial Authentication in Kerberos(PKINIT),” June 2006,[12] Rahul Jassal, “Wrapped RSA Cryptography Check on Window Executable usingReconfigurable Hardware”, International Journal of Computer Engineering & Technology(IJCET), Volume 3, Issue 3, 2012, pp. 291 - 299, ISSN Print: 0976 – 6367, ISSN Online:0976 – 6375.[13] M.A.Patel, Y.U.Kadam, R.Y.Thombare and H. P. Patil, “Defenses Against Large ScaleOnline Password Guessing Attacks by using Persuasive Click Points”, International Journalof Computer Engineering & Technology (IJCET), Volume 3, Issue 3, 2012, pp. 490 - 500,ISSN Print: 0976 – 6367, ISSN Online: 0976 – 6375.