About this Course

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Cryptography is an indispensable tool for protecting information in computer systems. In this course you will learn the inner workings of cryptographic systems and how to correctly use them in real-world applications. The course begins with a detailed discussion of how two parties who have a shared secret key can communicate securely when a powerful adversary eavesdrops and tampers with traffic. We will examine many deployed protocols and analyze mistakes in existing systems. The second half of the course discusses public-key techniques that let two parties generate a shared secret key. Throughout the course participants will be exposed to many exciting open problems in the field and work on fun (optional) programming projects. In a second course (Crypto II) we will cover more advanced cryptographic tasks such as zero-knowledge, privacy mechanisms, and other forms of encryption.

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Shareable Certificate

Earn a Certificate upon completion

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Approx. 23 hours to complete

English

Skills you will gain

Cryptography
Cryptographic Attacks
Public-Key Cryptography
Symmetric-Key Algorithm

Flexible deadlines

Reset deadlines in accordance to your schedule.

Shareable Certificate

Earn a Certificate upon completion

100% online

Start instantly and learn at your own schedule.

Approx. 23 hours to complete

English

Instructor

Instructor rating

4.77/5 (465 Ratings)

Dan Boneh

Syllabus - What you will learn from this course

Content Rating96%(20,442 ratings)

Week

1

Week 1

5 hours to complete

Course overview and stream ciphers

5 hours to complete

12 videos (Total 210 min), 2 readings, 2 quizzes

12 videos

Course Overview10m

What is Cryptography?15m

History of Cryptography18m

Discrete Probability (Crash Course)18m

Discrete Probability (Crash Course, Cont.)13m

Information Theoretic Security and The One Time Pad18m

Stream Ciphers and Pseudo Random Generators19m

Attacks on Stream Ciphers and The One Time Pad23m

Real-World Stream Ciphers19m

PRG Security Definitions24m

Semantic Security15m

Stream Ciphers are Semantically Secure [optional]10m

2 readings

Lecture slides for all six weeks10m

Course overview and additional reading resources10m

2 practice exercises

Week 1 - Problem Set30m

Week 1 - Programming Assignment [optional]30m

Week

2

Week 2

4 hours to complete

Block Ciphers

Week 2. We introduce a new primitive called a block cipher that will let us build more powerful forms of encryption. We will look at a few classic block-cipher constructions (AES and 3DES) and see how to use them for encryption. Block ciphers are the work horse of cryptography and have many applications. Next week we will see how to use block ciphers to provide data integrity. The optional programming assignment this week asks students to build an encryption/decryption system using AES.

4 hours to complete

11 videos (Total 167 min)

11 videos

What are Block Ciphers?16m

The Data Encryption Standard21m

Exhaustive Search Attacks19m

More Attacks on Block Ciphers 16m

The AES Block Cipher13m

Block Ciphers From PRGs11m

Review: PRPs and PRFs11m

Modes of Operation: One Time Key7m

Security for Many-Time Key (CPA security)22m

Modes of Operation: Many Time Key (CBC)16m

Modes of Operation: Many Time Key (CTR) 9m

2 practice exercises

Week 2 - Problem Set30m

Week 2 - Programming Assignment [Optional]30m

Week

3

Week 3

3 hours to complete

Message Integrity

Week 3. This week's topic is data integrity. We will discuss a number of classic constructions for MAC systems that are used to ensure data integrity. For now we only discuss how to prevent modification of non-secret data. Next week we will come back to encryption and show how to provide both confidentiality and integrity. This week's programming project shows how to authenticate large video files. Even if you don't do the project, please read the project description --- it teaches an important concept called a hash chain.

3 hours to complete

11 videos (Total 130 min)

Week

4

Week 4

4 hours to complete

Authenticated Encryption

Week 4. This week's topic is authenticated encryption: encryption methods that ensure both confidentiality and integrity. We will also discuss a few odds and ends such as how to search on encrypted data. This is our last week studying symmetric encryption. Next week we start with key management and public-key cryptography. As usual there is also an extra credit programming project. This week's project involves a bit of networking to experiment with a chosen ciphertext attack on a toy web site.

4 hours to complete

12 videos (Total 167 min)

12 videos

Active Attacks on CPA-Secure Encryption12m

Definitions 5m

Chosen Ciphertext Attacks12m

Constructions From Ciphers and MACs20m

Case Study: TLS 1.217m

CBC Padding Attacks14m

Attacking Non-Atomic Decryption 9m

Key Derivation13m

Deterministic Encryption14m

Deterministic Encryption: SIV and Wide PRP20m

Tweakable Encryption14m

Format Preserving Encryption12m

2 practice exercises

Week 4 - Problem Set30m

Week 4 - Programming Project [Optional]30m

Week

5

Week 5

3 hours to complete

Basic Key Exchange

Week 5. This week's topic is basic key exchange: how to setup a secret key between two parties. For now we only consider protocols secure against eavesdropping. This question motivates the main concepts of public key cryptography, but before we build public-key systems we need to take a brief detour and cover a few basic concepts from computational number theory. We will start with algorithms dating back to antiquity (Euclid) and work our way up to Fermat, Euler, and Legendre. We will also mention in passing a few useful concepts from 20th century math. Next week we will put our hard work from this week to good use and construct several public key encryption systems.

3 hours to complete

9 videos (Total 133 min), 1 reading, 2 quizzes

Week

6

Week 6

4 hours to complete

Public-Key Encryption

Week 6. This week's topic is public key encryption: how to encrypt using a public key and decrypt using a secret key. Public key encryption is used for key management in encrypted file systems, in encrypted messaging systems, and for many other tasks. The videos cover two families of public key encryption systems: one based on trapdoor functions (RSA in particular) and the other based on the Diffie-Hellman protocol. We construct systems that are secure against tampering, also known as chosen ciphertext security (CCA security). There has been a ton of research on CCA security over the past decade and given the allotted time we can only summarize the main results from the last few years. The lectures contain suggestions for further readings for those interested in learning more about CCA secure public-key systems. The problem set this week involves a bit more math than usual, but should expand your understanding of public-key encryption. Please don't be shy about posting questions in the forum. This is the last week of this Crypto I course. I hope everyone learned a lot and enjoyed the material. Crypto is a beautiful topic with lots of open problems and room for further research. I look forward to seeing you in Crypto II where we will cover additional core topics and a few more advanced topics.

4 hours to complete

11 videos (Total 155 min)

Week

7

Week 7

1 hour to complete

Final exam

1 hour to complete

Reviews

4.8

854 reviews

5 stars
84.95%
4 stars
12.15%
3 stars
1.60%
2 stars
0.56%
1 star
0.71%

TOP REVIEWS FROM CRYPTOGRAPHY I

by GKAug 6, 2016

Great into to the disciple for those of use who are interested in it but don't have access to a formal crypto class for what ever reason. This class made me fall in love with Coursera.

by AWJan 27, 2023

Wonderful introduction to cryptography in little time. Well presented. Interesting case studies and examples. Easy to follow. Well constructed assignments. Interesting programming assignments.

by FLApr 2, 2018

Very comprehensive overview of Cryptography. Though a bit too mathematical for me, the gist of it is very helpful to understand cryptocurrency protocol design of Bitcoin, Ethereum, Monero...

by LGDec 15, 2017

This course gives is perfect to start learning cryptography, explanations are detailed, topics carefully selected combining theory with real world examples and making emphasis in important details.

View all reviews

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Cryptography I

Cryptography I

About this Course

Skills you will gain