Back to Number Theory and Cryptography
University of California San Diego

Number Theory and Cryptography

A prominent expert in the number theory Godfrey Hardy described it in the beginning of 20th century as one of the most obviously useless branches of Pure Mathematics”. Just 30 years after his death, an algorithm for encryption of secret messages was developed using achievements of number theory. It was called RSA after the names of its authors, and its implementation is probably the most frequently used computer program in the world nowadays. Without it, nobody would be able to make secure payments over the internet, or even log in securely to e-mail and other personal services. In this course we will start with the basics of the number theory and get to cryptographic protocols based on it. By the end, you will be able to apply the basics of the number theory to encrypt and decrypt messages, and to break the code if one applies RSA carelessly. You will even pass a cryptographic quest! As prerequisites we assume only basic math (e.g., we expect you to know what is a square or how to add fractions), basic programming in python (functions, loops, recursion), common sense and curiosity. Our intended audience are all people that work or plan to work in IT, starting from motivated high school students.

Status: Public Key Cryptography Standards (PKCS)
Status: Encryption
BeginnerCourse17 hours

Featured reviews

TK

5.0Reviewed May 27, 2020

I cant think of any other best way of presenting cryptography to beginners. Everything presented in the course has some connection to cryptography, really enjoyed RSA quest.

AC

5.0Reviewed Nov 30, 2020

Excellent course to learn number theory principles and relate them to asymmetric cryptosystems. The course is highly rigorous and challenging.

TV

5.0Reviewed Feb 4, 2021

Thank you! enjoyed learning number theory, understood new concepts of modular programming, how public key -private key works and the basis of rsa algorithm.

GN

4.0Reviewed Dec 8, 2018

Amazing course, learnt a lot. The assignments were a bit difficult [ and time consuming ] but they helped me gain a better understanding of the concepts.

RD

5.0Reviewed Sep 17, 2020

Excellent material and teachers.Specifically, the course contents of week 4 : the RSA quiz and the RSA quest quiz material is outstanding! Kudos!

DP

5.0Reviewed Jul 29, 2020

This course was amazing! Got a good, but brief insight into the basics of cryptography. The examples at the end of the course were great!

AT

4.0Reviewed Nov 19, 2019

Final week is a bit rushed, think it would have benefited from being one week longer.Nevertheless, an excellent introduction to an extremely difficult and complex subject.

PS

5.0Reviewed Jun 13, 2020

Its a good course to the beginers of cryptography.If you want to join you should know basic number theory and computer language python.

SS

4.0Reviewed Apr 17, 2020

Great introduction to number theory, with little to no assumed knowledge. Proceeds quite quickly, but remains relatively simple and introduces concepts well.

WH

5.0Reviewed Apr 2, 2020

My first experience with cryptography. The coding assignments are enough to make me think and ensure that I understood the concepts.

PW

5.0Reviewed Nov 21, 2018

I was really impressed especially with the RSA portion of the course. It was really well explained, and the programming exercise was cleverly designed and implemented. Well done.

AS

4.0Reviewed Jul 5, 2020

It was a great course which helped me learn number theory and introduced me to Cryptography.The teaching assistants could have been more active.

All reviews

Showing: 20 of 134

Константин Касачёв
3.0
Reviewed Dec 19, 2017
Doug DesCombaz
2.0
Reviewed Dec 26, 2018
Steven Watson
5.0
Reviewed Dec 12, 2017
Liang Tan
5.0
Reviewed Jan 2, 2018
Prasad Kancharla
1.0
Reviewed Mar 19, 2019
Pedro Herrero-Vidal
5.0
Reviewed Jun 17, 2018
Pete Wills
5.0
Reviewed Nov 22, 2018
T KARTHIKEYAN
5.0
Reviewed May 28, 2020
Gholamreza Saberi Tabrizi
2.0
Reviewed Oct 16, 2018
William Higgins
5.0
Reviewed Apr 3, 2020
Ashish Sarode
5.0
Reviewed Jul 23, 2018
Jinqiang Zhang
5.0
Reviewed Dec 9, 2017
Tomasz Lewowski
5.0
Reviewed Sep 2, 2019
ANTHONY REID
4.0
Reviewed Jul 2, 2018
ID
1.0
Reviewed Jun 3, 2022
Nikita Skybytskyi
5.0
Reviewed Mar 25, 2021
Amy Gill
5.0
Reviewed Apr 24, 2020
Bhargav Das
5.0
Reviewed Dec 27, 2018
UMAR TABBSUM
5.0
Reviewed Mar 15, 2020
Srinath S
5.0
Reviewed Aug 1, 2020