An extended approach for SMS security using authentication functions

Nowadays, security of SMS is a crucial aspect because it plays an important role in value added services and mobile commerce. Asymmetric algorithm like Diffie-Hellman can be used to encrypt the SMS message in M-commerce or mobile banking system. We use authentication functions to maintain the integrity of data. Password key exchange protocol based on Diffie-Hellman algorithm generates a secret shared key which can be used in message encryption and in MAC function. MAC (message authentication code) or hash functions are used maintain the integrity of message and can be used with the encryption. These functions also act as an error detecting code or checksum. This paper discusses the comparative analysis of both the authentication functions separately for password key exchange protocol by analyzing some of the security issues. The discussion of this paper concludes that MAC functions are more secure than hash function, but having greater complexity and take more to execute. So, it´s better to use hash function for maintaining the integrity of message over a network where the transmitted amount of message is very small (SMS). Here, digital signature is generated with RSA to show the functionality of MD5 and SHA1, which prevents SMS from message modification and non-repudiation attack.