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Learner Reviews & Feedback for Cryptography I by Stanford University

4,250 ratings

About the Course

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....

Top reviews


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This is just a great course. The subject was new to me, and while it was difficult, I learned a lot and actually got a good grade.

Prof. Boneh is engaging and very clear in his explanations.


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Great intro to a complex topic.

It could be improved by having the programming assignments be:

+ Mandatory

+ More related to actual cryptographic algorithms/libraries (only some are)

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1 - 25 of 879 Reviews for Cryptography I

By Martin F J

Oct 11, 2017

I think this course was too difficult so those 6 weeks became much longer for me - maybe timeconsumption was 12 weeks. So that is my only criticism. This course could in my opinion have been divided into "Cryptography basics" and "Cryptography 1". On the other hand, I know Stanford is a good university, I just wish I had been informed about a course that could more easily have introduced me to the topic. This is/was my first cryptography course, so it was a very hard task for me to go through... But the instructor seems very good in his research field and many people recommend this course, thanks.

By Naresh B D

Apr 4, 2017

Professor is very knowledgable but he is fast... Even before i can understand the first line. he is on the fourth line. i find Hard to keep up with him. I am dropping this course.

By Camille G

Feb 9, 2018

I really enjoyed this course!

I was glad to work on prime numbers and RSA, even if it was quite late in the course.

I would not recommend it for everyone, though. It is definitely not for beginners; you need a mathematical mind and a solid maths knowledge. So, overall more difficult than what I expected.

Some things could be improved:

- the description of the course could go into more details (maybe with an entertaining short video?), especially regarding the requirements level mentioned above and the overall difficulty level you can expect

- a *formatted* transcript would be awesome

- sometimes, Dan speaks too fast or his writing is not 'top-notch'

- repeating the major concepts, and repeating them in a different way each time, could be done more frequently

- the audio track has been edited and can be 'bumpy' sometimes + do not hesitate to insert more pauses!!

- the course is a bit theoretical and could use more real-life, very concrete applications

Furthermore, at some stages of the course, it is hard to see the 'big picture'. We get the latter at the very end.

Also, keep in mind that the tests are not way easier than the corresponding lessons... quite the contrary actually.

I must highlight two very useful things during the course: recaps at the beginning of some videos, and 'graphical' explanations.

Finally, I had some good laughs hearing Dan state 'it's not that hard', 'it's not that difficult to see' or 'this is a pretty straightforward proof'... Reminded me of my old advanced maths classes.

By Sophia L

Mar 18, 2020

It requires knowledge of how cryptography works and the terms used to describe cryptography. I would not recommend it as a beginner course.

By Jewellia H

Dec 22, 2016

This isn't a beginners course. I dropped out in first week. I took every note I could and reviewed again and again. I really think the instructor is an intelligent man, but I'm not quite sure he understands how to teach well. I'm really disappointed that I didn't get to take anything away from this class.

By Bernardo C d A C

Mar 11, 2017

Cutting edge cryptography topics. Good explanations and slides, but pause button is highly recommended. Can be a bit too mathematical for the general public, and not very formal for mathematicians.

By Lewis C L

May 8, 2017

There were too many repititions of tautological proofs. Should have been covered in 1/2 or more of a single session: this is how we reason about cryptography. Too much focus on low-level primitives which doesn't make sense if we are to never implement our own cryptography. Finally, as a general point it would be amazing if there were ungraded "practice sets" that came with answers: you work it work them out and look at the answers and if you don't understand you try to figure out what you can't get. You can ask questions on the forum without revealing anything. The focus should be on working problems. Then, the quiz needn't permit infinite retrials: working through the practice sets is where the learning would occur. As it is now, you listen to the lecture, read over the notes several times, and then try the quiz. I did the programming before taking the quiz: that was a chance to actual work with the crypto algorithms.

By nikhil g

Jul 7, 2018

There should be examples regarding to assignment questions i.e. there should be examples similar to assignment questions

By Richard K

Jan 5, 2017

Very theoretical and mathematical and not enough real examples.

By Ashwani K

Aug 4, 2019

Only theory No practicals or solved questions

By Ben P

Sep 14, 2020

Excellent introduction to cryptography for those with little to no prior knowledge of the subject.

Would recommend becoming familiar with number theory as a precursor, as this underpins many of the concepts introduced. While not essential (as the basics are covered and references are provided to support material), the focus is much more on cryptography than mathematics.

Lectures are well structured and build on each other in a logical progression. Exercise questions are well thought out, and effectively test understanding of the modules. I would also recommend undertaking the optional programming exercises, as these tend to throw up practical issues that may not always be apparent from the course notes.

By Lucio C G

Dec 16, 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.

By Manjunath S

Apr 21, 2018

Should have come with an explanation that non IT background people cannot apply

By Nancy Y M

Jan 22, 2019

This course is very well explained and stimulating. I am a third year maths undergraduate in the UK. Although I did find some concepts from computer science very foreign in the very beginning, I soon picked them up. So don't be afraid if you are like me who don't know much about computer science. Staying active and curious is the key. Good luck with the course and I hope you enjoy it as much as I do. And here I would like to say thank you to Dan Boneh for making the videos and making this course public. I am looking forward to take Cryptography II in this autumn.

By Blake H

Jan 14, 2020

Provides a comprehensive introduction to cryptographic history, current technology, best practices and known attacker techniques. A great deal of material is covered in a relatively compact program.

By Tyler H

Dec 15, 2016

A really hard class for anyone not graduated from collage.

By Gethro O

Apr 28, 2020

Instructor does not know how to teach at all. Too fast, near to zero authentic explanations about any topic. He is knowledgeable, I'll give him that. But this course forces you to basically suffer if you want to actually understand the material fully - by having to replay the videos over and over again.

Also, the mathematical notations he use are understandable, but not standard. He makes them up, lol.

Disappointed in this course :(

By Enrico S

Jul 16, 2018

The course is excellent! Exactly what you would expect from a world-class institution like Stanford.

Prof. Boneh masterfully guides you through the core building blocks of cryptography, beautifully weaving the concepts into a logical framework that helps understanding the big picture and the role that each plays. The course is very rigorous but the math is not overwhelming and also discusses very useful practical topics like common cryptographic protocols (TLS, WEP, etc.) and the attacks that were discovered over the years.

The course is challenging and takes quite a bit of effort, but at the end I feel that I learned a lot. While I probably need some more time and practice exercises to fully absorb the material, I feel that from here I could go on and independently dig deeper in some of the topics or tackle more advanced one.

Looking forward to part II!

By William M

Sep 23, 2020

Edit: I could shorten it out to a summary:

"The most valuable course I ever enrolled in, this website and course is so extremely vital, I recommend anyone interested in cryptography to enroll in this course. " - William M



I would recommend ANYONE TO TAKE THIS COURSE, even if you're just beginning in Cryptography, I was hooked after the first day of "intro" about what ciphers are, how they work, and how you break them.

Again, can't say this enough; this course was, and is VITAL! As it's so extremely well made!


By Michael S

Jan 20, 2017

El profesor es muy malo explicando, hay cosas las cuales no tenian sentido (creo yo que esto es porque justamente el profesor no sabe y explicar) y ademas las preguntas que hace en medio de los videos son ridiculas. Da preguntas sin haber antes explicado el conocimiento previo.

By Alex W

Apr 24, 2021

The course assumes a solid understanding of university mathematics. I see reviews saying he just makes up mathematical notation, but he isn't, the professor assumes an understanding of Discrete Mathematics. If you haven't taken a Group Theory or Rings and Fields class you will not understand this course. It's not written anywhere, and the professor never says it. You are better off reading a textbook.

By Lorenzo B

Sep 18, 2020

Only two downsides imho: first, the course is fast - he does warn in the very first week that for some reason he goes faster doing a video course than in a real classroom, but it's worth repeating that there's a lot more stuff than one would guess by the video length.

Second, some questions are not perfectly synced, ie the choices appear after the answer is shown - eg

integrity-3-PMAC and the Carter-Wegman MAC at 5:14,

how-to-use-block-ciphers 2 - MANY-time key at 21:02,

how-to-use-block-ciphers 2 - MANY-time key at 12:22,

how-to-use-block-ciphers 1 - ONE time key 6:37. If anyone can fix them, thank you. Great course anyway!

By Justin P

Dec 31, 2018

I'm a software developer - I took this course because I wanted to demystify cryptography, and it delivered 100%. It describes fundamental cryptographic primitives, how to use them (and how not to use them) with real-world examples, as well as the theory behind why they are secure, and what "secure" actually means.

There is a fair amount of mathematics involved - everything is covered in the course, but someone with a background in mathematics will definitely have an easier time.

By Dragos R

Feb 20, 2019

It's been a great learning experience. My background in math / algebra / calculus is rather weak, so it was a real stretch. But it's so rewarding to understand how the fabric of our daily interactions is protected (or how vulnerable it can be) with modern cryptography. Kudoz to the teacher!

By Suraj B

Jun 12, 2017

The Cryptography I is a very formal course taught by a very accomplished professor, Dr. Dan Boneh of the Stanford University. He explains the inner workings of cryptosystems through mathematical structures and proofs. This way we are able to appreciate and fully understand crypto algorithms and their limitations. He covers topics in cryptography ranging from the ancient ciphers to modern public key cryptography and everything in between. This is cryptography at its core. Thank you, Dr. Dan Boneh!