## Information Mathematics Seminar

Seminar information archive ～12/10｜Next seminar｜Future seminars 12/11～

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

Organizer(s) | Toshiyuki Katsura |

**Seminar information archive**

### 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.

### 2023/01/12

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

Theory of fault-tolerant quantum computing II (Japanese)

**Yasunari Suzuki**(NTT)Theory of fault-tolerant quantum computing II (Japanese)

[ Abstract ]

To demonstrate reliable quantum computing, we need to integrate

quantum error correction techniques and achieve fault-tolerant quantum

computing. In this seminar, I will explain the basics of fault-tolerant quantum

computing and recent progress toward its experimental realization.

To demonstrate reliable quantum computing, we need to integrate

quantum error correction techniques and achieve fault-tolerant quantum

computing. In this seminar, I will explain the basics of fault-tolerant quantum

computing and recent progress toward its experimental realization.

### 2022/12/22

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

Theory of fault-tolerant quantum computing I (Japanese)

**Yasunari Suzuki**(NTT)Theory of fault-tolerant quantum computing I (Japanese)

[ Abstract ]

To demonstrate reliable quantum computing, we need to integrate quantum error correction techniques and achieve fault-tolerant quantum computing. In this seminar, I will explain the basic of fault-tolerant quantum computing and recent progress towards its experimental realization.

To demonstrate reliable quantum computing, we need to integrate quantum error correction techniques and achieve fault-tolerant quantum computing. In this seminar, I will explain the basic of fault-tolerant quantum computing and recent progress towards its experimental realization.

### 2022/12/08

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

Near-term quantum algorithms and quantum error mitigation (Japanese)

**Suguru Endo**(NTT)Near-term quantum algorithms and quantum error mitigation (Japanese)

[ Abstract ]

The current or near-term quantum computing devices are still small and noisy. In this talk, I will near-term quantum algorithms and quantum error mitigation for improving computation accuracy.

The current or near-term quantum computing devices are still small and noisy. In this talk, I will near-term quantum algorithms and quantum error mitigation for improving computation accuracy.

### 2022/12/01

16:50-18:35 Room #123 (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 Shor’s algorithm for factoring and discrete logarithm, quantum money, and verification of quantum computation based on cryptography.

I explain several topics on quantum computing and cryptography including Shor’s algorithm for factoring and discrete logarithm, quantum money, and verification of quantum computation based on cryptography.

### 2022/11/24

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

Attacks for lattice problems assuring the security of lattice-based cryptography (Japanese)

**Masaya Yasuda**(Rikkyo Univ.)Attacks for lattice problems assuring the security of lattice-based cryptography (Japanese)

[ Abstract ]

Lattice-based cryptography is one of post-quantum cryptography, and it is useful for construction of high-functional encryption such as fully homomorphic encryption. In this talk, I introduce methods to attack lattice problems assuring the security of lattice based cryptography. Specifically, I present algorithms of lattice basis reduction such as LLL and BKZ that are required for solving lattice problems. I also describe how to apply reduction algorithms to attacking LWE and NTRU problems.

Lattice-based cryptography is one of post-quantum cryptography, and it is useful for construction of high-functional encryption such as fully homomorphic encryption. In this talk, I introduce methods to attack lattice problems assuring the security of lattice based cryptography. Specifically, I present algorithms of lattice basis reduction such as LLL and BKZ that are required for solving lattice problems. I also describe how to apply reduction algorithms to attacking LWE and NTRU problems.