## Information Mathematics Seminar

Seminar information archive ～07/24｜Next seminar｜Future seminars 07/25～

Date, time & place | Thursday 16:50 - 18:35 128Room #128 (Graduate School of Math. Sci. Bldg.) |
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Organizer(s) | Toshiyuki Katsura |

**Seminar information archive**

### 2024/02/08

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Current status of quantum computing and its applications (Japanese)

**Keita Kanno**(QunaSys Inc.)Current status of quantum computing and its applications (Japanese)

[ Abstract ]

In this seminar, current status and future prospects of quantum computing and its applications will be presented.

In this seminar, current status and future prospects of quantum computing and its applications will be presented.

### 2024/01/25

16:50-18:35 Room #056 (Graduate School of Math. Sci. Bldg.)

Design and control of fault-tolerant quantum computer (Japanese)

**Yasunari Suzuki**(NTT)Design and control of fault-tolerant quantum computer (Japanese)

[ Abstract ]

To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we explain methods to fault-tolerantly control encoded logical information and methods to translate practical algorithms to basic operations.

To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we explain methods to fault-tolerantly control encoded logical information and methods to translate practical algorithms to basic operations.

### 2024/01/11

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Introduction to quantum computation and quantum error correction (Japanese)

**Yasunari Suzuki**(MTT)Introduction to quantum computation and quantum error correction (Japanese)

[ Abstract ]

To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we introduce the basic theory of quantum computation and quantum error-correcting codes.

To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we introduce the basic theory of quantum computation and quantum error-correcting codes.

### 2023/12/21

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Quantum Computing and Cryptography (Japanese)

**Takashi Yamakawa**(NTT)Quantum Computing and Cryptography (Japanese)

[ Abstract ]

I explain several topics on quantum computing and cryptography including quantum money and verification of quantum computation based on cryptography.

I explain several topics on quantum computing and cryptography including quantum money and verification of quantum computation based on cryptography.

### 2023/12/14

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Functional encryption and attribute-based encryption (Japanese)

**Junichi Tomida**(NTT)Functional encryption and attribute-based encryption (Japanese)

[ Abstract ]

I will explain the basics and the recent progress of functional encryption and attribute-based encryption.

I will explain the basics and the recent progress of functional encryption and attribute-based encryption.

### 2023/12/07

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Cryptographic Program Obfuscation and Its Applications (Japanese)

**Ryo Nishimaki**(NTT)Cryptographic Program Obfuscation and Its Applications (Japanese)

[ Abstract ]

I will explain what cryptographically secure program obfuscation is, how to achieve it, and its applications in this talk.

I will explain what cryptographically secure program obfuscation is, how to achieve it, and its applications in this talk.

### 2023/11/16

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Isogeny graphs on superspecial abelian varieties: Eigenvalues, Connection to Bruhat-Tits buildings, and Property (T) (Japanese)

**Takuya Yamauchi**(Tohoku Univ.)Isogeny graphs on superspecial abelian varieties: Eigenvalues, Connection to Bruhat-Tits buildings, and Property (T) (Japanese)

[ Abstract ]

For each fixed integer $g\ge 2$, a prime $p$, and all primes $\ell$ with $\ell\neq p$, we can consider finite regular directed graphs associated with the set of equivalence classes of $\ell$-marked principally polarized superspecial abelian varieties of dimension $g$ in characteristic $p$. In this talk, I will explain that we can study such graphs in terms of the corresponding Bruhat-Tits buildings. I also discuss the eigenvalues values of the random walk matrices in view of the theory of automorphic representations when $g=2$. This is a joint work with Y. Aikawa (Tokyo university) and R. Tanaka (Kyoto university).

For each fixed integer $g\ge 2$, a prime $p$, and all primes $\ell$ with $\ell\neq p$, we can consider finite regular directed graphs associated with the set of equivalence classes of $\ell$-marked principally polarized superspecial abelian varieties of dimension $g$ in characteristic $p$. In this talk, I will explain that we can study such graphs in terms of the corresponding Bruhat-Tits buildings. I also discuss the eigenvalues values of the random walk matrices in view of the theory of automorphic representations when $g=2$. This is a joint work with Y. Aikawa (Tokyo university) and R. Tanaka (Kyoto university).

### 2023/11/09

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Mathematical Aspects of Isogeny-Based Cryptography (Japanese)

**Katsuyuki Takashima**(Waseda Univ.)Mathematical Aspects of Isogeny-Based Cryptography (Japanese)

[ Abstract ]

I will explain mathematical aspects of isogeny-based cryptography.

I will explain mathematical aspects of isogeny-based cryptography.

### 2023/11/02

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Algorithms for solving lattice problems and their applications (Japanese)

**Masaya Yasuda**(Rikkyo Univ.)Algorithms for solving lattice problems and their applications (Japanese)

[ Abstract ]

In this talk, I introduce lattice algorithms such as LLL and BKZ reduction algorithms,

which are mandatory for solving lattice problems. I also describe how to solve LWE and

NTRU problems using lattice algorithms. In addition, I describe an application of lattice

algorithms for solving the integer factorization problem.

In this talk, I introduce lattice algorithms such as LLL and BKZ reduction algorithms,

which are mandatory for solving lattice problems. I also describe how to solve LWE and

NTRU problems using lattice algorithms. In addition, I describe an application of lattice

algorithms for solving the integer factorization problem.

### 2023/10/19

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Mathematical Aspects of Lattice-Based Cryptography (Japanese)

**Katsuyuki Takashima**(Waseda Univ.)Mathematical Aspects of Lattice-Based Cryptography (Japanese)

[ Abstract ]

I will explain mathematical aspects of lattice-based cryptography.

I will explain mathematical aspects of lattice-based cryptography.

### 2023/10/05

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Cryptography and Blockchain (Japanese)

**Tatsuaki Okamoto**(NTT)Cryptography and Blockchain (Japanese)

[ Abstract ]

Explanation of cryptography and blockchain

Explanation of cryptography and blockchain

### 2023/07/13

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Fully Homorphic Encryption and Functional Encryption (Japanese)

**Tatsuaki Okamoto**(NTT)Fully Homorphic Encryption and Functional Encryption (Japanese)

[ Abstract ]

Explanation of fully homorphic encryption and functional encryption

Explanation of fully homorphic encryption and functional encryption

### 2023/07/06

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Cryptographic protocols (Japanese)

**Tatsuaki Okamoto**(NTT)Cryptographic protocols (Japanese)

[ Abstract ]

Explanation of cryptographic protocols

Explanation of cryptographic protocols

### 2023/06/29

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Zero-knowledge proofs (Japanese)

**Tatsuaki Okamoto**(NTT)Zero-knowledge proofs (Japanese)

[ Abstract ]

Explanation of the theory of zero-knowledge proofs

Explanation of the theory of zero-knowledge proofs

### 2023/06/22

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Lattice-based cryptography (Japanese)

**Tatsuaki Okamoto**(NTT)Lattice-based cryptography (Japanese)

[ Abstract ]

Explanation of lattice-based cryptography

Explanation of lattice-based cryptography

### 2023/06/15

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Cryptosystems based on elliptic curves (Japanese)

**Tatsuaki Okamoto**(NTT)Cryptosystems based on elliptic curves (Japanese)

[ Abstract ]

Explanation of crypto-systems based on elliptic curves

Explanation of crypto-systems based on elliptic curves

### 2023/06/08

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Security, construction and proof of digital signatures (Japanese)

**Tatsuaki Okamoto**(NTT)Security, construction and proof of digital signatures (Japanese)

[ Abstract ]

Explanation of security, construction and proof of digital signatures

Explanation of security, construction and proof of digital signatures

### 2023/05/25

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Security, construction, and proof of public-key encryption (2) (Japanese)

**Tatsuaki Okamoto**(NTT)Security, construction, and proof of public-key encryption (2) (Japanese)

[ Abstract ]

Explanation of security, construction and proof of public-key encryption

Explanation of security, construction and proof of public-key encryption

### 2023/05/18

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Security, construction, and proof of public-key encryption (1) (Japanese)

**Tatsuaki Okamoto**(NTT)Security, construction, and proof of public-key encryption (1) (Japanese)

[ Abstract ]

Explanation on security, construction, and proof of public-key encryption

Explanation on security, construction, and proof of public-key encryption

### 2023/05/11

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

The security definition and proof of symmetric key encryption and public key encryption (Japanese)

**Tatsuaki Okamoto**(NTT)The security definition and proof of symmetric key encryption and public key encryption (Japanese)

[ Abstract ]

Explanation of the security definition and proof of symmetric key encryption and public key encryption

Explanation of the security definition and proof of symmetric key encryption and public key encryption

### 2023/04/27

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

The basics of cryptography II (Japanese)

**Tatsuaki Okamoto**(NTT)The basics of cryptography II (Japanese)

[ Abstract ]

Explanation of the basics of cryptography

Explanation of the basics of cryptography

### 2023/04/20

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

The basics of cryptography (Japanese)

**Tatsuaki Okamoto**(NTT)The basics of cryptography (Japanese)

[ Abstract ]

Explanation of the basics of cryptography

Explanation of the basics of cryptography

### 2023/04/13

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

Certification and signature

------Foundation of cryptography (Japanese)

**Tatsuaki Okamoto**(NTT)Certification and signature

------Foundation of cryptography (Japanese)

[ Abstract ]

Explanation on certification and signature.

Explanation on certification and signature.

### 2023/04/06

16:50-18:35 Room #128 (Graduate School of Math. Sci. Bldg.)

The role of cryptography (Japanese)

**Tatsuaki Okamoto**(NTT)The role of cryptography (Japanese)

[ Abstract ]

Explanation of the theory of cryptography

Explanation of the theory of cryptography

### 2023/01/19

16:50-18:35 Room #123 (Graduate School of Math. Sci. Bldg.)

Code-based cryptography and its decoding algorithm (Japanese)

**Shintaro Narisada**(KDDI Research, Inc.)Code-based cryptography and its decoding algorithm (Japanese)

[ Abstract ]

This talk overviews code-based cryptography and its decoding algorithm called Information Set Decoding (ISD). All lectures will be given in Japanese.

This talk overviews code-based cryptography and its decoding algorithm called Information Set Decoding (ISD). All lectures will be given in Japanese.