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Implementation of public key cryptography in kerberos with prevention of security attacks
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Implementation of public key cryptography in kerberos with prevention of security attacks

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synopsis:Implementation of public key cryptography in kerberos with prevention of security attacks

synopsis:Implementation of public key cryptography in kerberos with prevention of security attacks

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    Implementation of public key cryptography in kerberos with prevention of security attacks Implementation of public key cryptography in kerberos with prevention of security attacks Document Transcript

    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 248 IMPLEMENTATION OF PUBLIC KEY CRYPTOGRAPHY IN KERBEROS WITH PREVENTION OF SECURITY ATTACKS Er. Abhijeet1 , Mr. Praveen Tripathi2 , Er.Anuja Priyam3 , Er.Vivek kumar4 1 M. Tech. Computer Science Student, Kanpur Institute of Technology Kanpur, 2 Assistant Professor Computer Science Student, Kanpur Institute of Technology Kanpur 3 M. Tech. Computer Science Student, Kanpur Institute of Technology Kanpur 4 M. Tech. Computer Science Student, Kanpur Institute of Technology Kanpur ABSTRACT Use of Public key cryptography is the limitation of Kerberos and by using symmetric key cryptography there is some attacks, Replay attack and password attacks are serious issues in 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 the total Kerberos environment. In this Thesis we present an improved method which prevents replay attacks and password attacks by using Public Key Cryptography (both RSA and Diffie-Hellman Key Exchange algorithm). Keyword: Kerberos, Password attack, public key cryptography, PKINIT, Replay attack, Authentication Server. 1. INTRODUCTION Providing security services to the user in a secure way is an issue. Attackers can easily gain information during its transmission across the network and then gain unauthorized access to the servers, to whom they are not able to access. So, in this scenario, servers should be able to authenticate all requests for services. Authentication is a way of ensuring that no one 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 which does the task of authentication. Security involves Implementation of measures to protect attacks. 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: www.iaeme.com/ijcet.asp Journal Impact Factor (2013): 6.1302 (Calculated by GISI) www.jifactor.com IJCET © I A E M E
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 249 But it does not mean that an attack will never occur. For example, preventing an outside attacks doesn’t’ mean that you are secure, attacks may occur from inside of organization. Researchers have proved that many attacks occur from inside of the organization. Therefore, it is necessary to provide security inside of an organization. Authentication protocol is one of the most classical single sign-on protocols. Authentication is the base of secure network environment. Kerberos originated by MIT Project Athena [1] is one of the most widely-adopted authentication protocols. The overall scheme of Kerberos is that of a trusted third party that uses a protocol based on that proposed by Needham and Schroeder [2] . A single sign-on system means that a user can access all services from the application servers after only sign on one time in a multiple application systems. Kerberos V5 is being used at present but there are lots of replay and password attack problems in it. Kerberos V5 was designed to overcome some of the deficiencies of Kerberos V4, but it can’t guarantee to avoid replay and password attack. 2. LITERATURE SURVEY 2.1 OVERVIEW OF KERBEROS PROTOCOL Kerberos [6] is the authentication protocol between a server and client through a trusted third party in an open network environment. Based on Needham and Schroeder’s model, the Authentication server (AS), the trusted third party shares secret keys with all entities and authenticates the users with the secret keys. When a client requests authentication from it, the server grants a ticket encrypted with a pairwise key between the server and the client, and authenticates the client. The client authenticates itself with the Ticket Granting Server (TGS) by delivering the ticket received from the AS. The TGS issues a Service Granting Ticket after authenticating the client for service, and the client requests a service from the server by presenting this SGT. Finally, the server provides the service after verifying this 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 allows Kerberized applications to take advantage of existing key services and identity management.
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 250 2.2 Replay and Password attacks Many schemes have been proposed to prevent replay attack in Kerberos authentication protocol. Jian [2] proposed an optimized way to prevent password attack and replay attack in single Signon system. Multiple databases were added to provide the authentication 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 Application server. TGS and Application server, each has their own database. They store these tickets in their 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 password based sign-on protocol was proposed [3]. That protocol makes use of two passwords that are needed during the user registration and log files concept was used. Log file contained the details 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 and forwards to authentication server even after responding the user. Authentication server passes this log file to clients. Similarly, Authentication server also passes its log file. Therefore, a user can make a judgment on security of password through auditing log files and allowed to modifying the password. So, if an attacker has captured a password, client can easily change it by looking and analyzing at the log files. In [4], a concept is provided to prevent replay attack in Kerberos by using a freshness which makes use of new Symbolic Model Verifier. Location based Kerberos authentication protocol is described in [5]. In this approach server captures P(Y) code off all the client in the network and it assigns ticket granting ticket to the client by encrypting session key( used for communication between TGS and client) and TGT with the P(Y) code of user. After receiving this message, client accepts its P(Y) code using GPS and decrypts the message. So, if an attacker is able to capture the message, then he will not be able to decrypt the message because P(Y) code length is in several of gigabits. It will result in the failure of the ticket due to time synchronization problems. Here, user physical location is added as an additional message into the Kerberos protocol, which helps to determine physical location of the message provider. Server sends (TGT) to client by encrypting session key with the hash value of user physical location. So, even if an attacker captures a message, he will have to break two phase security to get session ticket and in this process, ticket time may expire. Capturing user physical location and adding it as a new authentication factor into the Kerberos Protocol method [7] was proposed to prevent replay attack. It used N-BAN logic (modified version of BAN logic [6]) to apply on the modified Kerberos protocol. Benjamin [8] proposes a method for the inspection of replay attacks on Kerberos authentication protocol in which the protocol was specified by using the Object-Z. Modified Symbolic Model verifier [9] approach was presented to find problems with respect to the replay attack. Some basic principles [10] were defined which are necessary to be used while designing the cryptography protocols. Five different strategies are presented. By using these strategies it is possible to design cryptographic protocols which show robustness against different classes of replay attacks. A new protocol for key distribution was proposed [11] after analysing the security flaws with different protocols that are currently used for the authentication as well as for key distribution. This proposed model is based on using symmetric keys.
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 251 2.3 PKINIT(Public Key Cryptography for Initial Authentication in Kerberos)[11] Pkinit provides support for using public-key authentication with Kerberos. Pkinit is useful in the following situations: 1. Using smart cards for Kerberos authentication 2. Authentication based on soft tokens (or certificates stored on a computer) instead of passwords 3. In conjunction with anonymous kerberos and FAST protecting password exchanges to remove the possibility of dictionary attacks. This article describes minimal Pkinit configuration for a KDC and clients. It assumes you already have a Kerberos realm functioning and that you have the openssl command available. The following steps are involved: 1. Setting up a certificate authority 2. Generating a KDC certificate 3. Generating client certificates 4. Configuring the KDC and clients 5. Testing Pkinit requires a public key infrastructure. The simplest use of Pkinit (anonymous kerberos) requires a certificate authority (CA) certificate and a KDC certificate. The certificate authority certificate is known by all clients; any certificates signed by this certificate are trusted 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 user will need a certificate as well. 3. PROPOSED ALGORITHM Here 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 clients registered on AS server. Both AS(authentication server) and TGS(ticket granting server)maintain its database. AS database contains ID of all registered clients, corresponding password and public key. TGS database contains a set of prime numbers and corresponding primitive roots and all real server with its password. The steps of algorithms is given below
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 252 Where Ticket for TGS contain-(client id, client network address, ticket validity period, and client/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. CONCLUSIONS After using public key cryptography in this way we can prevent Kerberos from security attacks like password or reply attack. This is also a new way of Implementing Public Key Cryptography in Kerberos. REFERENCES [1]Y. Kirsal, and O. Gemikonakli, “Further Improvements to the Kerberos Timed Authentication 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 of computers,” 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 , http://www.ietf.org/rfc/rfc4120.txt. [4] Eric Cole, Ronald L. Krutz, James Conley, Brian Reisman, Mitch Ruebush, Network security Fundamentals (John Wiley & Sons, ISBN 978-0-470-10192-6, 2008) [5] B. Clifford Neuman, Theodore Ts‘o, Kerberos: An Authentication Service for Computer Networks, 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 International Conference on Information Assurance and Security, PP. 495-498, IEEE 2009 [8] Yang Jian, An Improved Scheme of Single Sign-on Protocol Based on Dynamic Double Password, International Conference on Environmental Science and Information Application Technology, IEEE 2009. PP. 572-575. [9] S. Adyanthaya, S. Rukmangada, A. Tiwari and S. Singh, Modeling Freshness Concept to overcome Replay Attack in Kerberos Protocol using NuSMV, International Conference on Computer & Communication Technology IEEE-2010
    • International Journal of Computer Engineering and Technology (IJCET), ISSN 0976- 6367(Print), ISSN 0976 – 6375(Online) Volume 4, Issue 3, May – June (2013), © IAEME 253 [10] Abdelmajid, N.T., Hossain M.A, Shepherd S, Mahmoud K, Location-Based Kerberos Authentication Protocol, IEEE International Conference on Social Computing / IEEE International 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, http://www.ietf.org/rfc/rfc4556.txt. [12] Rahul Jassal, “Wrapped RSA Cryptography Check on Window Executable using Reconfigurable 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 Scale Online Password Guessing Attacks by using Persuasive Click Points”, International Journal of Computer Engineering & Technology (IJCET), Volume 3, Issue 3, 2012, pp. 490 - 500, ISSN Print: 0976 – 6367, ISSN Online: 0976 – 6375.