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  • NEHA NARULA: OK, so let's get started.

  • OK?

  • So great.

  • We're here to talk about cryptocurrency

  • engineering and design.

  • I think the first question that comes up that's very obvious

  • is what is a cryptocurrency?

  • So this word was kind of invented 10 years ago when--

  • I don't know how many of you know the origin story of where

  • bitcoin came from, but basically a pseudonym on the internet

  • dropped a paper and some open source code

  • in a forum on an email list, and said, hey,

  • I have this idea for this thing called bitcoin.

  • It's kind of like electronic cash.

  • Here's how I think it could work,

  • and here is some code if you want to run it and become part

  • of this peer-to-peer network.

  • We don't know who this person is.

  • This person has basically virtually disappeared

  • from the internet and from the world.

  • But it's created something that has captured

  • so many people's imaginations and has sort of, depending

  • on how you measure it, created billions

  • and billions of dollars of economic value

  • and inspired a lot of people to think about how

  • to use this technology to solve a myriad of different problems,

  • not just electronic payments.

  • So cryptocurrencies and the technology behind them

  • are inspiring people to think about how to bank the unbanked,

  • add more auditability and traceability to our world,

  • get rid of trusted intermediaries and institutions

  • in certain situations, and basically solve

  • every problem, if you read about what blockchains

  • can do on the internet.

  • Now that's not exactly what this class is about.

  • This class is not going to be about applications.

  • This class is going to be about technology and infrastructure.

  • You're going to learn how to create a cryptocurrency, what

  • goes inside a cryptocurrency, what's important,

  • what are the techniques.

  • And what application you choose to apply that to down the line,

  • that's kind of up to you.

  • But we're not going to be doing digital identity or health care

  • records or something like that.

  • We're going to be talking about the technology.

  • So a big question is how are cryptocurrencies

  • different from regular currencies?

  • And another thing that I want to make really clear

  • is that the terms in this space are still being defined.

  • So you will hear people throw around

  • all sorts of terms-- cryptocurrency, blockchain,

  • consensus.

  • And these words kind of have floating, evolving meanings

  • right now.

  • Part of that is because bitcoin, the first cryptocurrency,

  • didn't come from academia, as far as we know.

  • It came from a community of enthusiasts on the internet.

  • And so it doesn't necessarily have the same basis and rigor

  • that we might expect from most of our academic fields

  • of study.

  • It's totally OK.

  • We're figuring it out as we go along.

  • And academia is really embracing this topic.

  • So if any of you are graduate students who

  • are looking for an area in which to do research,

  • I think basically, the number of papers

  • published on cryptocurrencies and blockchain technology

  • in respected academic venues is doubling every year.

  • So there's huge opportunity here.

  • So cryptocurrencies are not regular currencies.

  • They're not $1.00 or a pound or a euro,

  • what we normally think of as currency.

  • They're something different.

  • Bitcoin was sort of created out of nowhere.

  • And what does it mean to create a cryptocurrency?

  • Who says you can create a cryptocurrency?

  • What backs a cryptocurrency?

  • Why is it valuable?

  • Well, first, before we answer that question,

  • I just want to make it really clear what

  • this course is not about, OK?

  • We are not going to help you ICO.

  • If you are interested in ICO'ing, just go.

  • That's not what this class is going to be about.

  • We are not going to offer any trading advice.

  • We have zero opinions on whether you should buy bitcoin

  • now or sell or whatever, or zen cash,

  • or whatever all these things are.

  • So none of that.

  • Don't even ask us.

  • We're not interested.

  • And this class is not really going

  • to be about permissioned blockchains either.

  • Now you might not know what this term means yet,

  • and that's totally OK, but I just

  • want to make it clear that what we're talking about here

  • are cryptocurrencies.

  • They're open permission with systems in which there is

  • a token which has some value.

  • So that's what we're not going to do in the class.

  • So going back to--

  • and let me just pause there for a moment.

  • Let me pause and ask you if there are any questions so far

  • about what I've said.

  • Yeah.

  • AUDIENCE: Do they always have to have value?

  • NEHA NARULA: No, not at all.

  • And let's start to get into that.

  • So the question was do tokens always have to have value?

  • So I think, really, to understand

  • what are cryptocurrencies, what are tokens, what do they mean,

  • we have to talk about money.

  • And we have to talk about what money is and what it means.

  • So this is going to be very hand-wavy

  • and I'm sure not very satisfying to a real monetary economist.

  • But money developed-- there are a few different theories

  • about how money developed.

  • There is this thing called the coincidence of wants.

  • So maybe I have a sheep and Tadge has some wheat.

  • I am hungry and would like to make bread.

  • Tadge would really like to make a sweater.

  • And so we can barter, we can trade.

  • I have one set of goods that is useful to Tadge.

  • Tadge has another set of goods that are useful to me.

  • We can get together and make an exchange.

  • So that's fantastic.

  • Barter is incredibly important.

  • Barter has existed for a long time.

  • But what if Tadge doesn't have wheat, Tadge has vegetables,

  • and I don't want vegetables.

  • I want wheat.

  • But Tadge still wants the wool from the sheep.

  • How do we execute this trade?

  • We don't have a coincidence of wants.

  • We don't actually want the exact same thing from each other.

  • So some theories are that money evolved out of this problem.

  • And money can be represented in so many different ways.

  • Money, I think, was first created around 5000 BC,

  • so it's really, really, really old.

  • The things that represented money usually

  • had certain properties.

  • They were rare.

  • They were not easily reproducible.

  • People, at times, used things like shells or beads for money.

  • The first coins-- this is like a really interesting coin

  • that was developed.

  • Precious metals were often used for money.

  • And then eventually we sort of evolved

  • into what we think of as money now,

  • which is paper bills, currency.

  • Another theory of how money came about

  • is this idea of receipts, debt and credit.

  • So maybe I have a sheep, and I shear all of my sheep

  • and collect a lot of wool.

  • What I can do is I can store that wool somewhere.

  • And I can get a receipt from someone

  • from having stored that wool, and that receipt is of value.

  • It entitles the person who holds the receipt to the good that

  • is being stored.

  • And so another theory of money is

  • that money evolved out of these receipts,

  • trading these receipts back and forth.

  • Instead of taking all that wool with you,

  • you leave it in one place in a depository,

  • and the receipt acts as a bearer instrument.

  • Whoever owns it has access to the wool in the depository.

  • And so you can kind of see two different ideas

  • about what money is develop from this.

  • One is, well, it's a bead or a coin,

  • or something that I hold, something

  • physical that we've decided to assign value to

  • in and of itself.

  • And another idea is I'm going to use a trusted institution.

  • I'm going to deposit something with that institution,

  • and they are going to ensure the validity of that deposit

  • and manage who has access to that deposit.

  • So this doesn't really get at the question

  • that was originally asked, which is why do tokens have value.

  • But one thing I want to point out is--

  • well, a question I want to ask you guys, actually,

  • is why do these things have value?

  • Does anyone have any ideas?

  • Yes.

  • AUDIENCE: Because everyone agrees that they do.

  • NEHA NARULA: Because everyone agrees that they do.

  • Any other thoughts on why those things have value?

  • Yeah.

  • AUDIENCE: They're also backed by institutions

  • like the government.

  • NEHA NARULA: They're backed by institutions.

  • Say a little bit more about that.

  • What does that mean?

  • AUDIENCE: So the government's kind

  • of promising you to respect the value of that.

  • NEHA NARULA: OK.

  • The government's promising to respect the value of that.

  • Does anyone want to add to that or have another reason?

  • Yes.

  • And say your name.

  • I'm sorry, yeah.

  • AUDIENCE: Jared Thompson.

  • In the example of the dollar, the government

  • is willing to accept it as payment for taxes.

  • NEHA NARULA: Payment for taxes.

  • OK.

  • So that kind of connects the government thing.

  • AUDIENCE: Even if it had no value of any other sort,

  • it has value in that sense.

  • It's the last thing that holds up its value.

  • NEHA NARULA: OK, great.

  • Anybody else?

  • Yes.

  • AUDIENCE: I'm Paul.

  • I think those the three on the front of the dollar,

  • those have inherent value because they

  • might be more rare.

  • NEHA NARULA: They have value because they're rare.

  • OK.

  • Interesting.

  • All right.

  • So those are all really interesting ideas.

  • I think that those are all sort of properties

  • of what makes things valuable.

  • There are definitely things that are rare that are not valuable,

  • right?

  • I can think of some things that might be extraordinarily rare.

  • There's only one or two of them in the universe,

  • and you would have no interest in owning them whatsoever.

  • You wouldn't assign value to them.

  • Certainly it's really important that you can pay taxes

  • with this stuff because taxes is pretty much a requirement

  • of living in any country.

  • There are things that have value that you don't necessarily

  • use for taxes.

  • So that's a little confusing.

  • And then there's this idea that it's backed,

  • that it's backed by something.

  • And the dollar used to be backed by something.

  • And actually, if you look at $1.00,

  • I think it still says this, right?

  • It's backed by the full faith and credit of the United States

  • government.

  • TADGE DRYJA: They don't say that anymore.

  • NEHA NARULA: They don't say that anymore?

  • They used to say that.

  • But that's what a lot of people say about money.

  • It's backed by the full faith and credit of the United States

  • government.

  • What does that really mean?

  • I think what it all goes back to is