Quantum Cryptography

Lecture fall 2012/13

Instructor Dominique Unruh <<surname> at ut dot ee>
Teaching assistent
Prastudy Fauzi (but practice is given by Dominique)
Lecture Tuesdays 10:15-11:45, room 612 (lectures may sometimes be switched with tutorial)
Practice Wednesday 10:15-11:45, room 512
Course Material Lecture notes, blackboard photos, practice blackboard photos (zip; huge zip), and exam study guide.
Language English
Exam TBA
Contact Dominique Unruh <<surname> at ut dot ee>

Topics covered

See also the blackboard photos and the practice blackboard photos (zip; huge zip).
2012-09-04 (lecture) Introduction and motivation. (Slides pptx, pdf)
2012-09-05 (practice) Polarization filters in sequence, circular polarization.
2012-09-11 (lecture) Mathematics of single qubits. Elizur-Vaidman bomb tester.
2012-09-12 (practice) Enhanced Elizur-Vaidman bomb tester
2012-09-18 (lecture) Multi-qubit systems. Unitary operations on multi-qubit systems.
2012-09-19 (practice) Quantum teleportation.
2012-09-25 (lecture) Measurements on multi-qubit systems.
2012-09-26 (practice) Implementing classical functions in quantum circuits.
2012-10-02 (lecture) Deutsch's algorithm. Analysis of toy crypto protocol (started). Density operators (started)
2012-10-03 (practice) Density operators: how to extend the system, how to do measurements. Non-equal density operators imply distinguishability.
2012-10-09 (lecture) Toy crypto protocol (finished). Partial trace.
2012-10-10 (lecture) Superoperators. Statistical distance. Trace distance.
2012-10-16 (practice) Modelling an adversary's possible actions by using only unitaries.
2012-10-17 (practice) Defining and proving the security of a toy crypto protocol.
2012-10-23 (lecture) Security definition of quantum key distribution.
2012-10-24 (practice) Security definition (secrecy) of a message transfer protocol.
2012-10-30 (lecture) Proof of quantum key distribution (started).
2012-10-31 (lecture) Proof of quantum key distribution (continued).
2012-11-06 (practice) Security proof corresponding for the protocol from practice 2012-10-24
2012-11-07 (practice) Realizing the Bell test
2012-11-13 (lecture) Proof of quantum key distribution (finished). Sketch: entanglement purification.
2012-11-14 (practice) Computing the probability of guessing a key (in QKD without entanglement purification).
2012-11-20 (lecture) Impossibility of unconditionally secure quantum commitments.
2012-11-21 (practice) Impossibility of oblivious transfer (OT).
2012-11-27 (lecture) Commitments in bounded quantum storage model (BQSM). Min-entropy (uncertainty relation, chain rule).
2012-11-28 (lect.+pract.) Lecture: Security proof in BQSM finished. Min-entropy splitting. Practice: OT in BQSM
2012-12-04 (lecture) Quantum time vaults.
2012-12-05 (practice) Quantum time vault security: some proof steps
2012-12-11 (lecture) Shor's algorithm: order finding, factoring, discrete logarithm
2012-12-12 (practice) Discrete fourier transform: unitarity, frequency analysis
2012-12-18 (lecture) Quantum money


Your current amount of points in the homework can be accessed here (as soon as the first sheet has been corrected).
Out / due
Sep 11 / Sep 18, noon
Homework 1
Solution 1
Sep 19 / Sep 25, noon Homework 2
Solution 2
Sep 25 / Oct 2, noon Homework 3
Solution 3
Oct 2 / Oct 9, noon
Homework 4
Solution 4
Oct 13 / Oct 23, noon
Homework 5
Solution 5
Oct 23 / Oct 30, noon
Homework 6
Solution 6
Oct 31 / Nov 13, noon
Homework 7
Solution 7
Nov 20 / Nov 27, noon
Homework 8
Solution 8
Nov 27 / Dec 9, noon
Homework 9
Solution 9
Dec 6 / Dec 13, noon
Homework 10
Solution 10


In quantum cryptography we use quantum mechanical effects to construct secure protocols. The paradoxical nature of quantum mechanics allows for constructions that solve problems known to be impossible without quantum mechanics. This lecture gives an introduction into this fascinating area.

Possible topics include:


You need no prior knowledge of quantum mechanics. You should have heard some introductory lecture on cryptography. You should enjoy math and have a sound understanding of linear algebra.


[NC00] Nielsen, Chuang. "Quantum Computation and Quantum Information" Cambridge University Press, 2000. A standard textbook on quantum information and quantum computing. Also contains some quantum cryptography.

Further reading may be suggested during the course. See the "further reading" paragraphs in the lecture notes.