Elliptic curve cryptosystems are based on ECDLP (Elliptic curve discrete logarithm problem) for their security. The best known method to solve ECDLP (pollard's rho algorithm) is fully exponential therefore Elliptic Curve Cryptosystems require substantially smaller key sizes for equivalent security as compared to other public key cryptosystems (RSA, DSA). This paper discusses the technique of Elliptic Curve Cryptography (ECC). Due to its computational benefits such as faster computation, low power and memory consumption, bandwidth saving, ECC is best suited for mobile/wireless environments. The application of ECC in mobile devices and wireless networks has been discussed in the paper. A survey of various protocols based on ECC has been done in the paper which clearly depicts its increasing acceptance over other public key cryptosystems.