Akinori Hosoyamada

I am a researcher of cryptography at NTT Social Informatics Laboratories, NTT Corporation, Japan.

Contact e-mail address: akinori dot hosoyamada at protonmail dot com

Last update: September 30, 2021

Research Interests and Highlights

Currently I am interested in symmetric-key cryptography, especially in post-quantum security of symmetric-key schemes, e.g., cryptanalysis of block ciphers and hash functions using quantum algorithms, and post-quantum security proofs for mode of operations. The following list is the highlight of my recent results with co-researchers.

Impossibility of quantum fully-black-box reductions from collision-resistant hash functions to one-way permutations [HY20] (Best Paper Award @ Asiacrypt 2020).
Dedicated quantum collision attacks on concrete hash functions [HS20,HS21].
Quantum multicollision-finding algorithms for cryptographic hash functions [HSX17,HSTX19,HSTX20].
Quantum attack that takes advantage of Simon’s algorithm without quantum superposed queries to keyed oracles [BHNSS19].
(Post-)quantum security proofs of symmetric-key schemes, e.g., a qPRP security proof of the 4-round Luby-Rackoff (Feistel) construction [HY18,HI19,HI21a,HI21c].

So far most of my published results are related to (post-)quantum security of symmetric-key schemes, but I am also interested in other topics on cryptography both in the quantum and classical settings. (Basically I like pure/applied mathematics.)

Biography

Job Experience

2016.04 – present

Researcher, NTT Corporation. (NTT Secure Platform Laboratories -> NTT Social Informatics Laboratories)

Education

2018.10 – 2021.09

Doctor of Engineering from Nagoya University. (Supervisor: Tetsu Iwata / Doctoral Thesis: “Post-Quantum Provable Security in Symmetric-Key Cryptography”)

2014.04 – 2016.03

Master of Science from Kyoto University. (Major: Algebraic/Differential Topology)

2010.04 – 2014.03

Bachelor of Science from Kyoto University. (Major: Mathematics)

Papers (in English)

Peer-Reviewed International Conference (with proceedings)

[HI21a] Hosoyamada, A., Iwata, T.: On Tight Quantum Security of HMAC and NMAC in the Quantum Random Oracle Model. (CRYPTO 2021) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HS21] Hosoyamada, A., Sasaki, Y.: Quantum Collision Attacks on Reduced SHA-256 and SHA-512. (CRYPTO 2021) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[CHLS20] Cid, C., Hosoyamada, A., Liu, Y., Sim, S.: Quantum Cryptanalysis on Contracting Feistel Structures and Observation on Related-key settings. (INDOCRYPT 2020) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)] (Note: This paper’s results are obtained in a discussion group of ASK 2019.)
[HY20] Hosoyamada, A., Yamakawa, T.: Finding Collisions in a Quantum World: Quantum Black-Box Separation of Collision-Resistance and One-Wayness. (ASIACRYPT 2020, Best Paper Award) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HS20] Hosoyamada, A., Sasaki, Y.: Finding Hash Collisions with Quantum Computers by Using Differential Trails with Smaller Probability than Birthday Bound. (EUROCRYPT 2020) [Proceeding ver. (Springer LNCS)][Full ver. (IACR ePrint)]
[HI19] Hosoyamada, A., Iwata, T.: 4-Round Luby-Rackoff Construction is a qPRP. (ASIACRYPT 2019) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)] (Note: A major revision is made after the conference. Please see the full version for details.)
[BHNSS19] Bonnetain, X., Hosoyamada, A., Naya-Plasencia, M., Sasaki, Y., Schrottenloher, A.: Quantum Attacks without Superposition Queries: the Offline Simon’s Algorithm. (ASIACRYPT 2019) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint / arXiv)] See also [BHNSS20].
[HSTX19] Hosoyamada, A., Sasaki, Yu., Xagawa, K.: Improved Quantum Multicollision-Finding Algorithm. (PQCrypto 2019) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint / arXiv)]
[IHMSI19] Gembu, I., Hosoyamada, A., Matsumoto, R., Sasaki, M., Iwata, T.: Quantum Chosen-Ciphertext Attacks Against Feistel Ciphers. (CT-RSA 2019) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HY18] Hosoyamada, A., Yasuda, K.: Building Quantum-One-Way Functions from Block Ciphers: Davies-Meyer and Merkle-Damgård Constructions. (ASIACRYPT 2018) [Proceeding ver. (SpringerLNCS)] [Full ver. (IACR ePrint)]
[HS18a] Hosoyamada, A., Sasaki, Y.: Quantum Demiric-Selçuk Meet-in-the-Middle Attacks: Applications to 6-Round Generic Feistel Constructions. (SCN 2018) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HS18b] Hosoyamada, A., Sasaki, Y.: Cryptanalysis Against Symmetric-Key Schemes with Online Classical Queries and Offline Quantum Computations. (CT-RSA 2018) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HSX17] Hosoyamada, A., Sasaki, Yu., Xagawa, K.: Quantum Multicollision-Finding Algorithm. (ASIACRYPT 2017) [Proceeding ver. (Springer LNCS)] [Full ver. (IACR ePrint)]
[HA17] Hosoyamada, A., Kazumaro, A.; On Quantum Related-Key Attacks on Iterated Even-Mansour Ciphers. (IWSEC 2017) (Best Paper Award) [Proceeding ver. (Springer LNCS)] See also [HA19].

Peer-Reviewed International Conference (without proceedings)

[BHNSS20] Bonnetain, X., Hosoyamada, A., Naya-Plasencia, M., Sasaki, Y., Schrottenloher, A.: Quantum Attacks without Superposition Queries: the Offline Simon’s Algorithm. (QIP 2020, single-session talk) See also [BHNSS19].

Journals

[HI21b] Hosoyamada, A., Iwata, T.: Indifferentiability of SKINNY-HASH Internal Functions. Accepted to IEICE Trans. Fundam. Electron. Commun. Comput. Sci. ([ePrint])
[HI21c] Hosoyamada, A., Iwata, T.: Provably Quantum-Secure Tweakable Block Ciphers. IACR Trans. Symmetric Cryptol. 2021(1): 337-377 (2021) [Link] ([ePrint])
[HNS20] Hosoyamada, A., Naya-Plasencia, M., Sasaki, Y.: Improved Attacks on sLiSCP Permutation and Tight Bound of Limited Birthday Distinguishers. IACR Trans. Symmetric Cryptol. 2020(4): 81-118 (2019) [Link]([ePrint])
[HSTX20] Hosoyamada, A., Sasaki, Y., Tani, S., Xagawa, K.: Quantum algorithm for the multicollision problem. Theor. Comput. Sci. 842: 100-117 (2020) [Link] (Note: Preliminary versions of this paper appeared at ASIACRYPT 2017 [HSX17] and PQCrypto 2019 [HSTX20].)
[HA19] Hosoyamada, A., Aoki, K.: On Quantum Related-Key Attacks on Iterated Even-Mansour Ciphers. IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 102-A(1), 27-34 (2019) [Link] (Note: A preliminary version of this paper appeared at IWSEC 2017 [HA17].)

Preprints

Other Activities

Program Committee Member

Asiacrypt 2021, December 5-9, 2021, Singapore
IWSEC 2021, September 8-10, 2021, Virtual

Invited Seminar

2019.10

Dagstuhl Seminar 19421, Quantum Cryptanalysis, October 13 – 18, 2019, Schloss Dagstuhl, Wadern, Germany [Link]

Invited Talk (International)

2019.11

The 9th Asian-workshop on symmetric key cryptography, December 13 – 15, 2019, University of Hyogo, Kobe, Japan [Link]

Reports

2020.1

[H20] Hosoyamada, A.: Review and Evaluation of the Effect of Quantum Computers on the Security of Symmetric-Key Cryptographic Schemes. CRYPTREC Investigation Reports on Cryptographic Techniques in FY 2019. [Link] (in Japanese)

Awards

2020.12

Asiacrypt 2020 Best Paper Award.

2019.01

SCIS 2018 Paper Award.

2017.08

IWSEC 2017 Best Paper Award.