Keccak (/kɛtʃɑːk/)

1. Keccak (/kɛtʃɑːk/) 小组成员：吴楠 张龙祥 邹佳顺 王淦 报告人：王淦

2. Keccak Keccak is a cryptographic hash function designed by Guido Bertoni, Joan Daemen, Michaël Peeters(From STMicroelectronics), and Gilles Van Assche(From NXP Semiconductors) • Cryptographic /'kriptəu'græfik/ 密码的 • Cryptography /krip'tɔgrəfi/ 密码学 • Hash Function 哈希函数、散列函数 • STMicroelectronics 意法半导体 • NXP Semiconductors 恩智浦半导体

3. Hash Function A hash function is any algorithm or subroutine that maps large data sets of variable length to smaller data sets of a fixed length. For example, a person's name, having a variable length, could be hashed to a single integer. The values returned by a hash function are called hash values, hash codes, hash sums, checksums or simply hashes. • hash values 哈希值 • hash codes 哈希码 • hash sums 哈希和

4. Hash algorithms are used widely for cryptographic applications that ensure the authenticity of digital documents, such as digital signatures and message authentication codes. These algorithms take an electronic file and generate a short "digest," a sort of digital fingerprint of the content. A good hash algorithm has a few vital characteristics. Any change in the original message, however small, must cause a change in the digest, and for any given file and digest, it must be infeasible for a forger to create a different file with the same digest. • digital signatures 数字签名 • message authentication codes 消息认证码

5. Keccak NIST announced a public competition on November 2, 2007 to develop a new cryptographic hash algorithm called SHA-3. The competition is NIST’s response to advances made in the cryptanalysis of hash algorithms. On October 2, 2012, Keccak was selected as the winner of the NIST hash function competition. • NIST (National Institute of Standards and Technology)美国国家标准与技术研究院 • SHA (Secure Hash Algorithm)安全哈希算法 • Cryptanalysis 密码分析

6. Keccak is a family of hash functions that are based on the sponge construction and use as a building block a permutation from a set of 7 permutations. In this document, we specify these permutations, the Keccak sponge functions and the parameter values we propose for use in our SHA-3 candidates. We also give conventions for bit and byte numbering, for using the arbitrary-long output mode and for naming parts of the Keccak state. • Sponge construction 海绵建构 • Permutation (数学中)排列变化

7. Sponge construction • Absorbing phase 吸收阶段 • Squeezing phase 挤压阶段

8. Keccak • GF(2) (Galois Field of two elements) 二元伽罗瓦域

9. State 状态 • Plane 面 • Slice 片 • Sheet 板

10. Row 行 • Column 列 • Lane 道 • Bit 块

11. Keccak

16. Pad 填充

17. Padding rule • Multi-rate padding 多速率填充

18. Example of Keccak

19. The EndThank you