Daily supervisor: Kaushik Senthoor (r.k.senthoor[at]tudelft.nl)

Project supervisor: Stephanie Wehner

Today, secure data communication is necessary for running the digital world. The most commonly used cryptographic protocol for this purpose is the RSA protocol. This protocol exploits the computational complexity required for factoring large numbers to provide computational security. However quantum cryptographic protocols can provide the much stronger statistical security. In this project, we focus on how to implement one of the important cryptographic tasks called the oblivious transfer with existing quantum technology.
Oblivious transfer, or OT in short, is an important cryptographic task. An OT protocol can be used as a building block to design any secure function evaluation protocol between two parties. In an OT protocol, Bob has to download exactly one of the two files with Alice, without Alice knowing about which file is downloaded. Implementing OT is possible with quantum communication between Alice and Bob when Bob’s quantum memory is limited. But what if the devices used for measuring the quantum bits in such a protocol is compromised? To overcome this challenge, we need an OT protocol which is measurement-device independent (MDI). In this project, we look at the feasibility of implementing OT under this setting with existing photonic technology.

Oblivious Transfer: How to download only the C-th file SC from Alice without letting her know what C is?

Project Goals:

• Obtain a meaningful set of assumptions under which MDI-OT can be implemented using imperfect photon sources.
• Propose a valid MDI-OT protocol under these assumptions.
• If possible, develop an information theoretic analysis to study and improve the performance of such protocols.
Requirements:
• A basic understanding in quantum computing (qubits, measurement basis, bell states, etc..) will be essential for this project. Simple concepts from cryptography, information theory and photonics will be useful but these can be learnt during the project if you understand probability and linear algebra. performance of such protocols.

Reference:

[1] Jérémy Ribeiro, and Stephanie Wehner. On Bit Commitment and Oblivious Transfer in Measurement-Device Independent settings. arXiv e-prints, page arXiv: 2004.10515, April 2020.