Welcome to the lecture Privacy Preserving Cryptocurrencies.

We are now on lecture number 14 and I am Dominik Schröder.

So as always we start this lecture with a short summary of what we did in the previous

lecture and in particular previous lectures because we're going to terminate the chapter

with this video and then we're going to discuss what we're going to do in this class and we

take a short look at the outline of this class in general.

So in the last lecture we essentially finished the area of anonymization techniques for Bitcoin.

And in particular we studied here a technique or a paper called tumblebit.

So this in fact concluded that say the depending on how you count probably the third part of

this lecture and it concludes the techniques that we that are known for in order to achieve

anonymity slash privacy in the setting of Bitcoin.

So in particular the techniques that you have seen before included something like mixing

services.

You have seen techniques such as coin join and coin shuffle.

You have seen zero coin.

That was the technique where you could convert between a basecoin and a zero coin with the

hope to break the link during this conversion.

And tumblebit of course was the last one.

So these are all techniques that build on top of Bitcoin or somewhat Bitcoin right.

I mean zero coin works independently of the basecoin of the underlying basecoin but of

course we require certain compatibility.

So these techniques that were important and interesting because Bitcoin of course is the

largest cryptocurrency that is out there.

It's also the oldest one.

And of course it's the question what can we achieve in this very limited setting.

Nevertheless if we have seen right I mean it's very easy to reach the boundaries of

things that actually can be done.

And this is why in this lecture we're going to take a look at privacy preserving cryptocurrencies.

So these are cryptocurrencies that have privacy built in as a feature from the very beginning.

And therefore clearly the privacy or the level of privacy that one can achieve is significantly

higher than adding some layer on top of a cryptocurrency that didn't or wasn't was never

meant to achieve such a level.

So what is the problem of using just these techniques together with Bitcoin in the first

place.

Well the first obvious issue is regardless of which technique you use it's something

that you have to run on top of Bitcoin.

And ideally right you would like to use a cryptocurrency as you do it with your fiat

currency.

So privacy should not be something that you have to do on top where you have to invest

energy and you have to download the tools and use the corresponding wallets and find

people for mixing and so on and so forth.

Privacy should be something that comes very natural with the currency and should essentially

be there in some sense for free.

So in this lecture we will give an introduction to privacy preserving cryptocurrency which

means we will give a short overview of the following three cryptocurrencies.

The first one is Dash.

So Dash in some sense can be seen as the middle ground.

Yes it is a cryptocurrency that supports certain privacy features but as you will see it's

very very close to Bitcoin and we mentioned it first of all such that there is a nice

link to what we did before.