A.Gokul and N.Zahira Jahan 2019. Secure mobile payment transaction scheme using optimistic fair exchange (OFE) protocols with TPA model. International journal of intellectual advancements and research in engineering computations. 7, 1 (Mar. 2019), 762–768. DOI:https://doi.org/10.61096/ijiarec.v7.iss1.2019.762-768.