Quantum Money and Cryptography with Deletion
Stub. Quantum money (banknotes as unclonable quantum states, verified via a pseudorandom function and classical verification), the quantum Zeno effect and the Elitzur-Vaidman bomb tester as physical phenomena with cryptographic relevance, an adaptive attack on Wiesner's original quantum money scheme, quantum lightning (money nobody — not even the minter — can duplicate), and cryptography with deletion — certifying that encrypted data has been genuinely destroyed, not just forgotten.
Corresponds to Chapters 25.4–26, the course’s final topic. Quantum money exploits no-cloning directly: a banknote is an unclonable quantum state, verifiable (by the bank, or by anyone, in the public-key variants) via a protocol built from a pseudorandom function — security rests on forging being as hard as cloning an unknown state. The quantum Zeno effect (frequent measurement can “freeze” a quantum system’s evolution) and the Elitzur-Vaidman bomb tester (using interaction-free measurement to detect an object without a photon ever touching it) are covered as physical phenomena whose counterintuitive measurement behavior turns out to enable (and, via an adaptive attack, also threaten) quantum money schemes — specifically, an adaptive attack breaking Wiesner’s original construction. Quantum lightning strengthens the guarantee further: no party, not even the original minter, can produce two valid copies of the same quantum banknote. Closes with cryptography with deletion: new quantum primitives that let a party prove previously-encrypted data has been irrevocably deleted, a certification classical cryptography has no way to provide.
Outline (TODO — flesh out each)
- Quantum money — model and verification
- Quantum money from a pseudorandom function; security intuition
- The quantum Zeno effect
- The Elitzur-Vaidman bomb tester
- An adaptive attack on Wiesner’s quantum money
- Quantum lightning
- Cryptography with deletion