Udacity gives students the opportunity to create hands-on projects that can be
put into their portfolios and used to demonstrate their skills to future
employers. You'll have a personal coach who helps provide feedback on your
assignments and projects to assist you in reaching your goals and staying on
track in your online classes. Throughout your education experience, you'll be
able to track your development, complete in-class projects, have access to
interactive exercises and videos and ...

Udacity gives students the opportunity to create hands-on projects that can be
put into their portfolios and used to demonstrate their skills to future
employers. You'll have a personal coach who helps provide feedback on your
assignments and projects to assist you in reaching your goals and staying on
track in your online classes. Throughout your education experience, you'll be
able to track your development, complete in-class projects, have access to
interactive exercises and videos and earn a verified certificate at the end of
the course as proof of all that you've learned. You'll be learning from
knowledgeable professors across various schools and parts of the globe. Learn
about computer science from Dave Evans, an instructor at the University of
Virginia, or delve into app development with Samantha Ready, a Developer
Evangelist at Salesforce.com.

Cryptography is present in everyday life, from paying with a credit card to using the telephone. Learn all about making and breaking puzzles in computing.

Rankings are based on a provider's overall CourseTalk score, which takes into account both average rating and number of ratings. Stars round to the nearest half.

I took this course after the Dan Boneh's "Cryptography" class so I want to
compare them a little bit. This class is much more practical than
"Cryptography". What I mean by that is that this one has less proofs but a lot
more application examples how Cryptography may be used in the filesystems,
internet, in digital cash etc. This class has also harder but fun challenges.
Just to give you an example — one of them is to hack at least 6 RSA ciphers
from the 15 given and it took me couple of days to solve it. Experience with
Python is almost a must. The final exam is maybe the best exam I ever had — it
was as exciting as playing an adventure game and getting the final answer was
like fighting the final boss :) So I highly recommend this course for anyone
who deals with passwords and keys and security in his life but I also
recommend it for anyone else just because it's a lot of fun.

Good course, my first udacity course (after taking several coursera ones).
Loved the fact that I could just churn through it at my own pace (that is I
finished the course in about one week). Best thing about the class were the
challenge programming assignments and how he touched on very modern
cryptographic concepts. Second best thing; unlike the coursera course, spends
little to no time on formalism, but gets to interesting applications of
crypto. So you don't learn about "semantic security" or "deterministic
encryption" or the details of how symmetric encryption works (e.g., no Merkle-
Damgard construction; no work through of AES). Instead, you get a good quick
overview of stuff like if you had a symmetric block cipher here's how to
combine it (CBC, CTR, CFB) mode, Diffie-Hellman, and (textbook) RSA. Then
quickly jump into more advanced stuff like anonymous money (bitcoin),
anonymous voting, anonymous routing (tor), blind signature...
Good course, my first udacity course (after taking several coursera ones).
Loved the fact that I could just churn through it at my own pace (that is I
finished the course in about one week). Best thing about the class were the
challenge programming assignments and how he touched on very modern
cryptographic concepts. Second best thing; unlike the coursera course, spends
little to no time on formalism, but gets to interesting applications of
crypto. So you don't learn about "semantic security" or "deterministic
encryption" or the details of how symmetric encryption works (e.g., no Merkle-
Damgard construction; no work through of AES). Instead, you get a good quick
overview of stuff like if you had a symmetric block cipher here's how to
combine it (CBC, CTR, CFB) mode, Diffie-Hellman, and (textbook) RSA. Then
quickly jump into more advanced stuff like anonymous money (bitcoin),
anonymous voting, anonymous routing (tor), blind signatures, breaking GSM,
BEAST SSL attack, and secure multiparty communication. However, when going
through many of these topics he doesn't always clearly define assumptions (who
knows what information), threat model, power of attackers, etc. Worst thing
about the class: vague quiz questions. First, all questions were videos
reading a question to you aloud which is annoying format compared to being
able to read the question with its assumptions explicitly on the same page as
the answers when you try to answer. (Versus having to rewind). Next, the
questions only accepted one answer, and were occasionally subjective, and even
more rarely wrong (usually with an instructor's note at the bottom right of
the page that's easy to miss). E.g., at one point the answer to three decimal
digits was .327 and the system wouldn't accept "0.327" or "0.33", but you had
to put in "0.32"; at another point a derivation there was a sign error and no
options were correct. The answer often depends on unstated assumptions and
that you have to watch a video to hear the question, versus seeing it written
out with the assumptions actually spelled out. You just have to learn not to
take the questions too seriously, and have no problem getting the
vague/subjective ones wrong. Examples of bad questions include the first one
in the course: "Which of these involve cryptology: Opening a door, playing
poker, doing a google search, logging into udacity" (and the answer is all of
them). I had skipped the intro video (where he spoke "opening a door with a
key" (even though no key was written down) and that I'll buy when adding a
key, that is cryptology. But playing poker does not by traditional definitions
involve cryptology even though if it involves "secrets". Cryptology is the
combination of cryptography (secret writing) and cryptanalysis (how to break
cryptography without the key). Or another example, they do the standard proof
by contradiction that there's no maximal prime and instead an infinite number.
You first assume (wrongly) that you have a finite set of all primes. You
multiply them all the primes together and add one to that (e.g., P = p1 p2 p3
... pN +1) where p1 is the first prime, pN is the assumed maximal prime). At
this point, the lecture stops and asks "is p prime?" Yes, No, or Maybe. The
system would only accept "Yes" which has a perfectly logical argument (p is
greater than the assumed largest prime pN; so it can't be prime as we've
assumed all primes are smaller than pN). But you can also argue, that it must
not have any divisors with your finite list of prime numbers (since p mod p_i
= 1 for all p_i in your set and you would have p mod p_i = 0 work for some p_i
if p was composite), and if a number is not divisible by any prime number less
than itself, then it must be prime. So either option has a good argument
behind it, but only one answer works. The problems involving the actual
material often had similar issues from vaguness, poorly defined assumptions as
well. Anyhow, overall great recommended course; take away 0.5 stars from
vagueness of some questions and how assumptions about attacker/threat model
were often left unstated.

I jumped into this course straight after Udacity's CS101 (was a big fan of
Dave Evans after that one), and it was quite a jump in difficulty! I also took
a few weeks off in the middle, and the lack of continuity for me made it
difficult to get back into it. As with all Udacity's courses (that I've done
so far) the quality of the lecture material in this course is excellent. The
assignments were reasonable, except that each one had a challenge problem for
which the answer wasn't provided. I managed to do the first of these, but then
couldn't dedicate enough time to them over subsequent weeks to bother. This is
obviously a personal choice, and a complete learning experience from this
course would definitely involve the challenge questions. Just be prepared for
a lot of work (and some fun, I'm sure) in solving them. People on the forums
seemed to have spent days on these, but in return I'm sure they had some
practical crypto skills at t...
I jumped into this course straight after Udacity's CS101 (was a big fan of
Dave Evans after that one), and it was quite a jump in difficulty! I also took
a few weeks off in the middle, and the lack of continuity for me made it
difficult to get back into it. As with all Udacity's courses (that I've done
so far) the quality of the lecture material in this course is excellent. The
assignments were reasonable, except that each one had a challenge problem for
which the answer wasn't provided. I managed to do the first of these, but then
couldn't dedicate enough time to them over subsequent weeks to bother. This is
obviously a personal choice, and a complete learning experience from this
course would definitely involve the challenge questions. Just be prepared for
a lot of work (and some fun, I'm sure) in solving them. People on the forums
seemed to have spent days on these, but in return I'm sure they had some
practical crypto skills at the end of the course, whereas I feel (some months
after finishing it) that I only have an ideas of a few of the concepts. In the
global Udacity meetup, Dave Evans said that Udacity is planning an
intermediate level course to more effectively bridge the large gap between
CS101 and this one; until then, you may want to try some of the other
intermediate courses on Udacity before leaping into this one!

Rankings are based on a provider's overall CourseTalk score, which takes into account both average rating and number of ratings. Stars round to the nearest half.