• Definitions • Passwords – Unix Passwords – One time passwords • Challenge-response techniques

• What is “Information Security” • A brief history of Info sec • Threats、Attacks and Defenses

• Probability & statistics • Basic concepts in information theory • Linear Algebra

• Vector Space Model (VSM) • Latent Semantic Model (LSI) • Language Model (LM)

• How to collect data from Web? – Build a Crawler – High Performance Web Crawler – Distributed Crawling/Incremental Crawling – State-of-art technology

北京大学：《信息检索》课程教学资源（PPT课件讲稿）Web Search

北京大学：《信息检索》课程教学资源（PPT课件讲稿）Course Overview（主讲：闫宏飞）

• Symmetric Cryptography • Asymmetric Cryptography

• Principles of Public-Key Cryptosystems • The RSA Algorithm

复旦大学：《信息安全》教学课件_03 Modern Block Ciphers