Abstract. The past few years have seen the emergence of a large number of proposals for electronic payments over open networks. Among these proposals is the Secure Electronic Transaction (SET) protocol promoted by MasterCard and VISA which is currently being deployed worldwide. While SET has a number of advantages over other proposals in terms of simplicity and openness, there seems to be a consensus regarding the relative inefficiency of the protocol. This paper proposes a lightweight version of the SET protocol, called "LITESET". For the same level of security as recommended in the latest version of SET specifications, LITESET shows a 53.1/53.7% reduction in the computational time in message generation/verification and a 79.9% reduction in communication overhead. This has been achieved by the use of a new cryptographic primitive called signcryption. We hope that our proposal can contribute to the practical and engineering side of real-world electronic payments.