Quantum Cryptography

Lecture fall 2013/14

Instructor Dominique Unruh <<surname> at ut dot ee>
Lecture Tuesdays 10:15-11:45, room 512 (lectures may sometimes be switched with tutorial)
Practice Thursdays 12:15-13:45, room 612
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).
2013-09-03 (lecture) Introduction and motivation
2013-09-05 (practice)
Mathematics of polarized light and polarization filters
2013-09-10 (lecture) Mathematics of single qubits
2013-09-12 (practice) Elizur-Veidman bomb tester - enhanced version
2013-09-17 (lecture) Mathematics of multiple qubits
2013-09-19 (practice) Quantum teleportation
2013-09-24 (lecture) Measurements in subsystems. Deutsch's algorithm. Toy crypto example. Ensembles. Density operators
2013-09-26 (practice) Implementing classical functions as unitaries
2013-10-01 (lecture) Operations on density operators. Partial trace.
2013-10-03 (practice) Purification of quantum circuits.
2013-10-08 (lecture) Quantum operations. Statistical distance. Trace distance.
2013-10-10 (practice) Toy encryption protocol: security definition and proof.
2013-10-15 (lecture) Quantum key distribution (QKD): Idea. Security definition. Bell states. Start of construction/proof.
2013-10-17 (practice) Secure message transfer from QKD: Security definition.
2013-10-22 (lecture) QKD: Proof continued
2013-10-24 (practice) Secure message transfer from QKD: Security proof.
2013-10-29 (lecture) QKD: Proof finished. Entanglement purification (sketched). Commitments (definitions).
2013-10-31 (practice) Guessing the key in QKD without entanglement purification (started)
2013-11-05 (lecture) Impossibility of commitment (continued). Min-entropy. Uncertainty relation. Commitment in BQSM (started).
2013-11-07 (practice) Guessing the key in QKD without entanglement purification (finished)
2013-11-12 (lecture) Commitment in BQSM (finished). Chain-rule for min-entropy. Min-entropy splitting.
2013-11-14 (practice) Oblivious transfer in the BSQM.
2013-11-19 (lecture) Discrete Fourier Transform (DFT). Shor's algorithms for: Order finding. Factoring.
2013-11-21 (practice) Implementing the quantum DFT.
2013-11-26 (lecture) Zero-knowledge proofs: Classical definitions. Protocol for graph-isomorphism.
2013-11-28 (lecture) Quantum zero-knowledge proofs: Watrous' rewinding lemma. Security of graph-ismorphism protocol.
2013-12-03 (lecture) Wave function. Schrödinger equation. Particle in an infinite potential well.
2013-12-05 (practice) Spin. Doing an X-gate on a spin qubit.
2013-12-10 (lecture) Quantum position-verification: Impossibility classical & quantum. Possibility in BQSM (with criticism).
2013-12-12 (practice) Breaking a quantum position-verification protocol.
2013-12-17 (lecture) Quantum money: Wiesner scheme. Aaronson-Christiano scheme.
2013-12-19 (practice) Attacks on Wiesner's 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 12 / Sep 19
Homework 1
Solution 1
Sep 19 / Sep 25
Homework 2
Solution 2
Sep 24 / Oct 1
Homework 3
Solution 3
Oct 2 / Oct 8
Homework 4
Solution 4
Oct 9 / Oct 15
Homework 5
Solution 5
Oct 15 / Oct 22
Homework 6
Solution 6
Oct 22 / Oct 29 Homework 7
Solution 7
Oct 31 / Nov 5
Homework 8
Solution 8
Nov 6 / Nov 12
Homework 9
Solution 9
Nov 13 / Nov 19
Homework 10
Solution 10
Nov 20 / Nov 26
Homework 11 Solution 11
Nov 30 / Dec 9
Homework 12 Solution 12
Dec 11 / Dec 17
Homework 13 Solution 13


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.