Prevention of eavesdropping type of attack in hybrid communication system

#The present invention relates generally to communication security and, more particularly, to techniques for preventing an eavesdropping type of attack, such as a man-in-the-middle attack, in a hybrid communication system.

#It is known that the Universal Mobile Telecommunications System (UMTS) is a third generation communication network technology that was developed by 3GPP (3rd Generation Partnership Project) to improve upon its predecessor the Global System for Mobile Communication (GSM). A UMTS network utilizes a UMTS Terrestrial Radio Access Network (UTRAN) as the air interface (radio access technology) for mobile stations accessing a UMTS network, see, e.g., 25.xxx series of 3GPP standards. A GSM network utilizes a General Packet Radio Service (GPRS) as the air interface for mobile stations accessing a GSM network, see, e.g., 23.xxx series of 3GPP standards.

#Further, it is known that the Long Term Evolution (LTE) network is a 3GPP-specified network that was developed to improve upon the UMTS standard and provide an enhanced user experience and simplified technology for next generation mobile broadband. LTE radio access technology is known as Evolved UMTS Terrestrial Radio Access (E-UTRA) and the network is known as an Evolved Packet System (EPS). Details about E-UTRA may be found, by way of example, in the 36.xxx series of 3GPP standards.

#FIG. 1 illustrates an authentication and key agreement procedure for use when a mobile station accesses a network other than its home network.

#FIG. 2 illustrates a first phase of a man-in-the-middle attack.

#FIG. 3 illustrates a second phase of a man-in-the-middle attack with a methodology for preventing the attack according to an embodiment of the invention.

#Principles of the present invention realize the need to secure communications associated with hybrid communication systems. In the embodiments to follow, hybrid GSM/EPS, GSM/UMTS and GSM/UMTS/EPS systems will be used to illustratively describe the security techniques and mechanisms of the invention. However, it is to be understood that the principles of the present invention are not limited to hybrid communication systems with GSM and EPS and/or UMTS communication modes but rather are more generally suitable for a wide variety of other hybrid communication systems in which it would be desirable to prevent security attacks that may be launched due to the fact that one communication mode in the hybrid communication system implements weaker security than that of another communication mode in the hybrid communication system.

#As used herein, the phrase “hybrid communication system” generally refers to a communication system that supports two or more communication modes. “Communication mode” (or simply “mode”) generally refers to an operation mode that supports a particular radio access technology and/or network protocol that is used to provide communication and access features for a particular type of communication network. By way of example, communication modes that are part of an illustrative hybrid communication system described herein include a GSM communication mode and an EPS communication mode and/or a UMTS communication mode.

#Referring now to FIG. 1, an authentication and key agreement procedure is shown. This procedure 100 generally describes an authentication and key agreement protocol that occurs when a mobile station (MS) accesses a network (visited network) other than its home network. Procedure 100 generally shows an authentication and key agreement protocol that can be used in a hybrid communication system.