Interview: Blockchain Maven Marie Leaf

By Melissa Slaughter

Marie Leaf.jpeg

You’ve heard the word “blockchain” before, usually in regard to cryptocurrency. Personally, it makes me think of episodes of Black Mirror. But it turns out blockchain is an active part of our daily lives, even if we don’t realize it.

Marie Leaf, head of product at Kadena, works with blockchain every single day. I spoke with Marie over the phone for this issue to find out what blockchain is and how it relates to the world.



Let's get started. First, who are you and what do you do?

My name is Marie Leaf and I am the head of product at Kadena, a blockchain company.

Amazing. And what makes you Hapa?

My mom is Malaysian...she kind of looks Chinese. It's like the original Chinese-Malaysian. It's like a really small subset and then my father has Ashkenazi-Jewish roots in Eastern Europe. He was born in upstate New York.

That's amazing. Most of the people I know who are Hapa are also part Jewish.

There's this whole study around how Jewish and Asian cultures are very compatible. So I joke, I'm like a Jew-boo. I was actually born in Indonesia, when my dad was doing some work and then I grew up mostly in Vancouver and a little bit in Shanghai.

So you kind of were surrounded by Asian people, mixed people, a diverse community, right?

Yeah. I would say my three best friends growing up in elementary and high school were all half-Asian. And then I was always the awkward white kid growing up which was weird because Vancouver has such a high Asian population that when I went to university [in Montreal], I was now the token Asian friend whereas before I was awkward white kid. I thought that was an interesting experience growing up.

Did you go to school for computer science or technology?

I did not. I had always been very technically inclined. I got really interested technology. I studied international economics and development economics to be specific as well as political science. And it has a big role in blockchain. I joke it's the political science of computers.

And I realized that in economic growth models that the big factor that really changes what makes or breaks or defines how a community leapfrogs or grows economically comes down to the technology (whether that's agricultural tech or whether it's biotech or what we saw in the past decade) was really information technology and access to information.

So after I graduated I was like, I just want to be closer to the technology. And I moved to Silicon Valley. I moved to Berkeley and San Francisco, and just learned by osmosis and kind of living in a lot of hacker houses.

I was working in corporate finance at the time. And then I kind of got a little bit oversaturated with tech living in the middle of San Francisco. That was like... This is too kind of provincial and I was like, I need to understand the world that software is trying to eat. So I up and moved to New York and I started working in operations at a large systems integrator and then I sort of worked my way up.

Then I taught myself. I took a couple of Udacity courses [in machine learning], teaching myself full stack engineering. I fell in love with machine learning as well as blockchain.

I always thought Bitcoin was cool. But blockchain, with the promise of Ethereum as the world computer, was kinda mind-blowing to me. And one of my honors theses was in social networks and the kind of network modeling of trust systems in Southeast Asia.

Think about companies either contributing or providing a service along the lines of trust or access. A bank provides trust; you can (somewhat) trust that your money is being held in that bank.

But what the internet did is gave us access to a ton of information. But in a way, arguably, it even bastardized access to trust. So knowing what information was real and knowing how to own your own data. That is what blockchain is injecting back into the system. It's what Tim Berners-Lee or people who made the foundations of the internet wish they had built the internet [on in the first place].

So you've thrown down a lot of great ideas. You've talked about the economy and politics and technology outside of computers and machine learning. And of course blockchain, which is what you specialize in.

I feel like you might have said it, but can you define in layman's terms what is blockchain?

So, a blockchain is actually very simple. A lot of what complicates it for a lot of people is the arms race to building the blockchains. People keep defining it in new ways.

A blockchain is a set of replicated databases that a community holds, that a network maintains, and it has a mechanism where the nodes vote on the state and truth of the ledger at the transactions. That's what makes it immutable….That just means you can't just change transactions on the ledger because the ledger is replicated and it's exactly the same across all the different nodes.

OK. I don't know if I understood that. When you say ledger what does that mean?

It's like an Excel document of different transactions between people. Alice has paid Bob. And Bob has paid Alex this amount.

So when someone goes in and changes it and says Bob paid X amount and then changes it to Y amount...

The entire network has to agree to make that agreement. They have to pay a little bit of work, pay a little bit of money in the form of, say, electricity to ensure that they're not replicating a bad transaction.


And if you add a bad transaction to the network then your block doesn't get rewarded for the energy you put into paying that transaction.

So, say you're sharing an Excel document. Someone puts in incorrect formatting and it breaks the formatting they would then break the ledger, right?

They would break the ledger on their own node. So this is where it gets interesting. There's different types of blockchains. So let's not get into a proof of work and how it maintains the truth at the ledger. But just know that there is a replicated log, a replicated sort of account of history of the transactions of one blockchain since the beginning of that blockchain’s time.

OK. You said Excel sheets, which is what most people are using on a day-to-day basis. It's also used in social networks. What other day-to-day usage would a lay person who doesn't work in tech be using that’s related to blockchain?

So, the components of blockchain technology have been around for 20 years. You know, like applied cryptography, Merkle proofs, voting mechanisms. But it's how they were sliced together that makes it novel. So that innovation really is not on the technical level. There are some innovations happening at the technical level but that's not what makes it so powerful.

It's a lot. More people underestimate or underplay this, but it's a lot more innovative on the sociopolitical aspect. This was sort of highlighted by Bitcoin as a first-use case of a blockchain. And Bitcoin as in money, as in being tradable for fiat currency.

So Bitcoin is just a good example where usually a central bank determines how much money is in supply and they determine the capital controls coming in and out of the country now. Bitcoin is not owned by any country. It's just owned by the network itself.

And the network agrees that the common shared chain is the ledger. Yes?

Correct. So it's when you have a $5 bill, you don't actually own that $5 bill. That $5 bill is essentially a derivation loan against your belief in the U.S. economy.

Yes, that makes sense.

Yeah. So when you own a Bitcoin, it is still your belief in the Bitcoin network to maintain itself. But you actually have power to mine it and you actually own-own that Bitcoin. Nobody else has access to it.

So the U.S. government cannot (I mean, now they have taxes and regulations about it) but theoretically, no one other than you own that share… So in the same way that only you own your money data. I mean money is essentially data.

The next level of applications on blocking are, for example, user data. So all the data that Facebook, Google, all these large companies have about you, there is this thesis or inspiration for people to just start taking back control and owning their own data. So your cell phone number, or height, your birthdays, all of that. That sits on a cloud somewhere right now that Facebook and Google own and they package it and they use it to sell to gain revenue in ad generation.

So with blockchain you can actually now be that, (they call it sovereign identity) where you get you choose what information you give to people. And now you can monetize that on a piecemeal basis.

And we're just exploring how to make them interoperate. We're exploring the different economics between different sorts of blockchains that serve different use cases.

You said you have a degree in political science economics. Why do you think people should go into this industry. Particularly, you're a woman in what I'm guessing is a heavily male-dominated industry.

I was thinking about new forms of currency before Bitcoin came out and when Bitcoin came out, I think I was part of this generation that was very disillusioned by the whole sort of financial system and the derivatives and how derivatives are just synthetic derivatives that aren't really representative of helping the economy other than by large bankers.

So part of it is like, let's save money to be more useful for the people that it serves. So the whole use case of guarding against inflationary shocks and in developing nations that's a huge M.O. and sort of interest for me just because I think globalization wasn't done right the first time. And I want to do it right [this time] and I think there's a lot of just asymmetries in the world that I do want to help solve.

[Secondly], I actually was not preparing to make a career in this. I was sort of at a crossroads between machine learning and watching.

And then the Dow attack happened and I realized, “Oh my God. This is a whole bunch of shady people just trying to hack each other and screw each other out of money.” And then I met Ari Juels who was the chief scientist at RSA for 10 years and he was like, “No...A lot of good actors and people are working on this.”

I got so fascinated by [blockchains’] promise to sort of touch on data silos and data on walls between countries, not only between countries, but between different tiers of the economy.

For example, it can better ticket monetization, [or] small and medium-sized businesses, which I find really interesting.

That's awesome.

[At Kadena], I think our tech team is 57% women. That's something I was really big on when I first joined: the way they value diversity. and it's not in the PR-marketing way. This is good for our company and this is good for building technology that is supposed to represent all types of life. We have a diverse team building it. It's been really great so far.

Lastly, I ask everyone, what's your favorite food, since we find that for Hapas, food is so relatable to all of us.

Surprisingly, it's none of my ethnic heritage. I would die happy just eating Japanese food for the rest of my life.




Melissa has lived in all four time zones in the contiguous United States. A former actor in Seattle, WA, Melissa now resides in NYC as a content creator. She is the producer of the We're Not All Ninjas podcast, which she also hosts with fellow Hapa Mag writer, Alex Chester. Melissa also writes for online blogs Nerdophiles and The Nerds of Color. Find her @NotAllNinjasPod.