[en] Quantum oblivious transfer (QOT) is an essential cryptographic primitive, but unconditionally secure QOT is known to be impossible. Here, we propose a practical QOT protocol which is perfectly secure against dishonest senders without relying on any technological assumptions. It is also secure against dishonest receivers in the absence of long-term quantum memory and complicated collective measurements. The protocol is extremely feasible, as it can be implemented using currently available Mach–Zehnder interferometers, and no quantum memory, collective measurements, or entanglement are needed for honest participants. More importantly, compared with other practical QOT schemes, our protocol has an unbeatable efficiency since it requires the transmission of a single photon only. (paper)