Quantum entanglement is a phenomenon available only at nanometer scale. In this paper, we show how quantum entanglement can be used to build cryptographic primitives such as oblivious transfer. In addition to studying the protocol itself, we also show how to realize some applications based on our proposal. These include typical e-Business applications such as contract signing, certified mail, simultaneous secret exchange, secure transaction and remote coin flip. Unlike classical oblivious transfer, the security of this protocol is based on physical laws, instead of any unproven mathematic conjecture. As a result, our proposal provides unconditional security for e-Business.