An extended approach for securing the Short Messaging Services of GSM using multi-threading elliptical curve cryptography Currently, mobile phones are not only used for formal communication but also for sending and receiving sensitive information. Short Messaging Service’s(SMS) are one of the popular ways of communication. Sending an SMS is easy, quick and inexpensive. However, when information is exchanged using SMS, protecting the short messages from the known attacks like man in the middle attack, reply attack and non-repudiation attack is very difficult. Such attacks on SMS security are hindering their application. This paper evaluates performance of elliptical curve cryptography by implementing it with threading and without threading. Based on the results of evaluation the one with the best performance is chosen for end to end SMS security.