Abstract: A method for performing spacetime-constrained oblivious transfer between various laboratories of a first party A and various laboratories of a second party B. The method includes providing the spacetime-constrained oblivious transfer to satisfy various conditions. The method further includes encoding, by the laboratories of the first party A, various messages in a quantum state selected from various non-orthogonal quantum states. The method further includes transmitting, by the laboratories of the first party A, the quantum state to a first laboratory of the second party B. The method further includes applying, by the first laboratory of the second party B, a quantum measurement on the quantum state to obtain a classical measurement outcome. The method further includes transmitting, by the first laboratory of the second party B, the classical measurement outcome to the laboratories of the second party B.

Abstract: A method for performing spacetime-constrained oblivious transfer between various laboratories of a first party A and various laboratories of a second party B. The method includes providing the spacetime-constrained oblivious transfer to satisfy various conditions. The method further includes encoding, by the laboratories of the first party A, various messages in a quantum state selected from various non-orthogonal quantum states. The method further includes transmitting, by the laboratories of the first party A, the quantum state to a first laboratory of the second party B. The method further includes applying, by the first laboratory of the second party B, a quantum measurement on the quantum state to obtain a classical measurement outcome. The method further includes transmitting, by the first laboratory of the second party B, the classical measurement outcome to the laboratories of the second party B.

Abstract: A method for performing spacetime-constrained oblivious transfer between a party A and a party B. The method includes imposing relativistic signaling constraints on a cryptographic task of one out-of-m oblivious transfer involving parties A and B. The method further includes using quantum systems for the one-out of-m oblivious transfer. The method guarantees unconditional security of the spacetime-constrained oblivious transfer, based on the imposed relativistic signaling constraints and based on using quantum systems for the one-out of-m oblivious transfer.

Abstract: A method for performing spacetime-constrained oblivious transfer between a party A and a party B. The method includes imposing relativistic signaling constraints on a cryptographic task of one out-of-m oblivious transfer involving parties A and B. The method further includes using quantum systems for the one-out of-m oblivious transfer. The method guarantees unconditional security of the spacetime-constrained oblivious transfer, based on the imposed relativistic signaling constraints and based on using quantum systems for the one-out of-m oblivious transfer.