Cyber Crime and Cyber Terrorism

270
CHAPTER 18
Evolution of TETRA
still problem. 802.1x defines the encapsulation of the Extensible Authentication 
Protocol (EAP), and enables authentication through third-party authentication serv-
ers such as Radius and Diameter. End-to-end security can be provided by use of 
Internet Protocol Security (IPSEC), Transport Layer Security (TLS), Secure Sockets 
Layer (SSL), Secure Shell (SSH), pretty Good Privacy (PGP), etc. Security of GSM 
and 3G suffers from similar compatibility problems with TETRA. GSM security de-
fines Subscriber Identity Module (SIM), the MS, and the GSM network. SIM hosts 
subscribe authentication key (K), Personal Identification Number (PIN), key genera-
tion algorithm (A8), and authentication algorithm (A3). MS contains the encryption 
algorithm (A5) for air interface. Encryption is only provided for the air interface. 3G 
security builds upon the security of GSM. It addresses the weaknesses in 2G systems 
with integrity and enhanced authentication as well as with enhanced encryption us-
ing longer keys and stronger algorithms. Seamless communication for crisis manage-
ment (SECRICOM—FP7) project partially addresses this challenge for secure push 
to talk systems over existing infrastructures (GSM, UMTS networks).
Another challenge in multi-technology communication is that the most of the 
security mechanisms are optional, and they are maintained based on the policies of 
different administrative domains. An end-to-end connection between two MS may 
go through an unsecure public network which may permit in variety of attacks in-
cluding denial-of-service and man-in-the-middle. Cost of mitigating these attacks 
on MS side may be higher than the benefit of the connection in terms of Quality of 
Service (QoS) and Quality of Experience (QoE) metrics. Therefore, QoS and QoE 
mechanisms must involve related metrics to provide predictable security service lev-
els to the end users (Spyropoulou, 2002).