---
author: Advanced Topics in Security and Privacy (CS 839)
title: Lecture 01
date: September 05, 2018
---

# Security and Privacy

## It's everywhere!

## Stuff is totally insecure!

## It's really difficult!

# What topics to cover?

## A really, really vast field
- Things we will not be able to cover:
    - Real-world attacks
    - Computer systems security
    - Defenses and countermeasures
    - Social aspects of security
    - Theoretical cryptography
    - ...

## Theme 1: Formalizing S&P
- Mathematically formalize notions of security
- Rigorously prove security
- Guarantee that certain breakages can't occur

> Remember: definitions are tricky things!

## Theme 2: Automating S&P
- Use computers to help build more secure systems
- Automatically check security properties
- Search for attacks and vulnerabilities

## Our focus: four modules
1. Differential privacy
2. Applied cryptography
3. Language-based security
4. Adversarial machine learning

# Differential privacy

## A mathematically solid definition of privacy
- Simple and clean formal property
- Satisfied by many algorithms
- Degrades gracefully under composition

# Applied crypto

## Computing in an untrusted world
- Proving you know something without revealing it
- Certifying that you did a computation correctly
- Computing on encrypted data, without decryption
- Computing joint answer without revealing your data

# Language-based security

## Ensure security by construction
- Programming languages for security
- Compiler checks that programs are secure
- Information flow, privacy, cryptography, ...

# Adversarial machine learning

## Manipulating ML systems
- Crafting examples to fool ML systems
- Messing with training data
- Extracting training information

# Tedious course details

## Class format
- Three components:
    1. Paper presentations
    2. Final project
    3. Class participation
- Annoucement/schedule/materials: on [website](https://pages.cs.wisc.edu/~justhsu/teaching/current/cs839/)
- Class mailing list: [compsci839-1-f18@lists.wisc.edu]()

## Paper presentations
- Sign up to lead a discussion on one paper
- Suggested topic, papers, and schedule on website
- Before each presentation:
    - I will send out brief questions
    - Please email me brief answers

> If you want advice, come talk to me!

## Final project
- Work individually or in pairs
- Project details and suggestions on website
- Key dates:
    - **September 19**: Pick groups and topic
    - **October 15**: Milestone 1
    - **November 14**: Milestone 2
    - **End of class**: Final writeups and presentations

> If you want advice, come talk to me!

## Todos for you
0. Complete the course survey
1. Check out the course website
2. Think about what paper you want to present
3. Brainstorm project topics

# Defining privacy

## What does privacy mean?
- Many meanings of privacy

## Why is privacy hard?

## Hiding private data
- Remove "personally identifiable information"

## Problem: not enough

## "Blending in a crowd"

## Problem: composition

## Differential privacy

## Basic definition