Paper 2017/977

Cryptanalysis against Symmetric-Key Schemes with Online Classical Queries and Offline Quantum Computations

Akinori Hosoyamada and Yu Sasaki


In this paper, quantum attacks against symmetric-key schemes are presented in which adversaries only make classical queries but use quantum computers for offline computations. Our attacks are not as efficient as polynomial-time attacks making quantum superposition queries, while our attacks use the realistic model and overwhelmingly improve the classical attacks. Our attacks convert a type of classical meet-in-the-middle attacks into quantum ones. The attack cost depends on the number of available qubits and the way to realize the quantum hardware. The tradeoff between data complexity $D$ and time complexity $T$ against the problem of cardinality $N$ is $D^2 \cdot T^2 =N$ and $D \cdot T^6 = N^3$ in the best and worst case scenarios to the adversary respectively, while the classic attack requires $D\cdot T = N$. This improvement is meaningful from an engineering aspect because several existing schemes claim beyond-birthday-bound security for $T$ by limiting the maximum $D$ to be below $2^{n/2}$ according to the classical tradeoff $D\cdot T = N$. Those schemes are broken if quantum offline computations are performed by adversaries. The attack can be applied to many schemes such as a tweakable block-cipher construction TDR, a dedicated MAC scheme Chaskey, an on-line authenticated encryption scheme McOE-X, a hash function based MAC H$^2$-MAC and a permutation based MAC keyed-sponge. The idea is then applied to the FX-construction to discover new tradeoffs in the classical query model.

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. CT-RSA 2018
post-quantum cryptographyclassical query modelmeet-in-the-middletradeoffChaskeyTDRkeyed spongeKMACFX
Contact author(s)
hosoyamada akinori @ lab ntt co jp
2018-01-09: revised
2017-10-05: received
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Creative Commons Attribution


      author = {Akinori Hosoyamada and Yu Sasaki},
      title = {Cryptanalysis against Symmetric-Key Schemes with Online Classical Queries and Offline Quantum Computations},
      howpublished = {Cryptology ePrint Archive, Paper 2017/977},
      year = {2017},
      note = {\url{}},
      url = {}
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