SIM cards have several features that enhance security for wireless communications networks. Smart-card supporters point to the potential of limiting or eliminating fraud as one of their strongest selling points.

SIM cards provide a secure authentication key transport container from the carrier’s authentication center to the end-user’s terminal. Their superior fraud protection is enabled by hosting the cryptographic authentication algorithm and data on the card’s microprocessor chip. SIM cards can be personal identification number (PIN) protected and include additional protection against logical attacks. With added PIN code security, SIM cards offer the same level of security used by banks for securing off-line payments.

Because the home network–authentication algorithm also resides in the card, SIM cards make secure roaming possible. They can also include various authentication mechanisms for internetwork roaming of different types.

Complete fraud protection (with the exclusion of subscription fraud) can only be provided in the context of a complete security framework that includes terminal authentication, an authentication center, and authentication key management. Smart cards are an essential piece of this environment, but only the complete architecture can allow fraud reduction and secure roaming.

Finally, it should be noted that biometric smart-card applications such as voice or fingerprint recognition could be added to provide maximum fraud prevention. Smart cards could then combine the three basic security blocks of possession, knowledge, and characteristics (see Figure 2).

Figure 2. Identification Model