# What should we learn next? | Journey into cryptography | Computer Science | Khan Academy

You’ve reached the first
checkpoint in the Journey to Cryptography series. And now I want to
talk about what’s next, because I’m
working on a new series. However, this one
won’t end here. And if anything, we’re kind
of at the beginning still. So I’m going to do three
different checkpoint videos. This one is on advanced lessons. However, I also want
challenges and what we can do with more interactive
explorations and computer science lessons as it
applies to cryptography. But for now, let’s talk
I don’t necessarily mean harder lessons. I mean more detailed. And let me give you a
conceptual idea for what I think this series could be,
and future series. I like to think of each series
as the trunk of a tree, where I took you from
prehistoric times to around the 20th
century, which is here, with a few different threads. And these ideas kind
of branch apart. Once you hit the 20th
and 21st century, they start getting
highly specific. And way down here on the leaves
are current research questions, which over here might
be problems related to prime number distribution,
and over here some very specific work being done
on randomized algorithms or hash functions. And, say, up here, we might
have new public key protocols because RSA was just the first. Or we also have encryption
standards such as DES and AES. We would have a whole new
branch on quantum cryptography. So as you can see, there’s
so many different things that branch out of this series. And I couldn’t possibly
do justice to them all. So I think of this video
as living right here. It’s kind of a junction point. Now I could branch
off with the help of the community and
possibly other video creators to fill out this tree gradually
over time, specifically with the help of the community. And I’m really excited about the
question and answer community and the work being done
to improve how people can help people on Khan Academy. So for example, in terms of
where one of these branches can go, I’ve noticed
clusters of questions kind of leading into a common branch. For example, under the
pseudo-random number generator– I have two
questions here, one by Sonnie and one by Drakain. Drakain’s question
is, “Why has he suggested that time
in milliseconds is a suitable random seed? This is a huge
no-no in security. The time it is on your
machine is the time is on my machine, give
or take 100 milliseconds, which can be brute
force attacked.” And again, this is a
great question, too, because it speaks to the
need that I didn’t present a cryptographically secure
pseudo-random generator. So the middle squares
method is back here in the early 20th century. But up till today, we are
not using the middle squares method. And that’s a whole
interesting branch. And it’s these sort
of questions which cluster together and
really drive new content. And I want to show you a
really interesting example of how this has
happened already. This is a question Samuel asked
on the One-Time Pad video. He said, “Wouldn’t a computer be
able to test all possibilities very fast?” And Chumpatrol basically
asked the same question here. I see this happening a
lot, similar questions. All speak to the
need of a new video. So I went and created a video
on perfect secrecy, which really nails down how you
can’t beat randomness in the world of encryption. And out of this video, Dawn
made a really great comment. And what they did was
basically summarize my video in two sentences. So this is what I want to try
to do more of in filling out these branches– take
questions, make new content, and have this kind of feedback
loop, and see what we can do. So now what I would
really love is for you to ask questions
below this video, which arise after watching
the entire series. So not specific details
about certain videos, those can go with the videos. But new questions,
which are kind of opening a new can of worms. And what I think
will be fun to do is your question
will lead to answers by both me and the
rest of the community. So we’ll have multiple answers. And what I can do is take
this body of answers, and out of this, draft
up a rough script for more advanced videos
on specific topics that subsets of the
community care about. So hopefully out
of the discussion below, over time we can
grow a bunch of new videos. And I want to be clear. This is an ongoing process. So this won’t happen
tomorrow or next week. I hope it can happen months
and even years from now. We can still be building out
new videos off this series, and these videos can be
a collaborative effort between myself and the community
and perhaps other video creators down the road. So let me know what you think
below and let’s get started.