International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Yi-Kai Liu

Publications

Year
Venue
Title
2018
CRYPTO
Pseudorandom Quantum States 📺
Zhengfeng Ji Yi-Kai Liu Fang Song
We propose the concept of pseudorandom quantum states, which appear random to any quantum polynomial-time adversary. It offers a computational approximation to perfectly random quantum states analogous in spirit to cryptographic pseudorandom generators, as opposed to statistical notions of quantum pseudorandomness that have been studied previously, such as quantum t-designs analogous to t-wise independent distributions.Under the assumption that quantum-secure one-way functions exist, we present efficient constructions of pseudorandom states, showing that our definition is achievable. We then prove several basic properties of pseudorandom states, which show the utility of our definition. First, we show a cryptographic no-cloning theorem: no efficient quantum algorithm can create additional copies of a pseudorandom state, when given polynomially-many copies as input. Second, as expected for random quantum states, we show that pseudorandom quantum states are highly entangled on average. Finally, as a main application, we prove that any family of pseudorandom states naturally gives rise to a private-key quantum money scheme.
2015
EUROCRYPT
2014
CRYPTO

Coauthors

Zhengfeng Ji (1)
Yi-Kai Liu (3)
Fang Song (1)