Category Archives: Blockchain

Some Notes on

Yesterdays I watched the video from Introduction of OpenMined by Andrew Liam Trask. Wow, it's so interesting. Some notes:

* First of all, unlike similar projects. There is no ICO. It's a genuine open source projects with a vibrant community.

* The idea is quite explainable. It's a marketplace between data scientists and miners who want to provide data. The key question Trask tried to figure out is to protect data privacy from the user, at the same time allow data scientists to train model securely.

* At first I thought it is just an idea about federated learning combined with deep learning. But Trask has augmented the idea with homomorphic encryption and smart contract. I am still in the process to learn why the last two concepts but briefly homomorphic encryption allows model to be securely to miners without getting stolen. Whereas having smart contract would genuinely allow an open market place.

* What if miner tries to come up with fake data? This is actually an FAQ on As it turns out, a data scientist can also specify a test set on the smart contract. This ensures data uploaded by miner improve a model.

* Another question I asked to their slack community is how everyone is paid without a coin. Currently the project would rely on USD, ETH and BTC. Fair enough.

Quick Impression of Princeton's Coursera "Bitcoin and Cryptocurrency Technologies"

Recently I have gone through all the video lectures from Princeton's Coursera "Bitcoin and Cryptocurrency Technologies" (BCT). Just like many of the courses I took in AI/DL, I want to write some notes on the class and whatabout. But since I won't call myself deep in the subject yet and I hadn't looked at the HW (no time...), so I decide to just write a quick impression.

- If you recall, Greg DubelaWaikit Lau and I started B&C as a satellite of AIDL. Greg Dubela is more a practicing programmer, Waikit Lau has quite a bit of experience on bitcoin. But I learn about cryptos mostly for fun. When we first started the group, part of the goal is to direct OoT traffic from AIDL to a proper place. We end up having 5k members now.

- And of course, the most frequently asked question at B&C is "What really is bitcoin?". (*)

- You may think of bitcoin as just a currency. If you have a bit of money, you can just trade it. That's pretty much is what 99% of the people should know about bitcoin.

- But then you can also see bitcoin as a kind of mineral. It just happens that your computer is the equipment to mine it. Again, depends on whether you like the idea of mining, that's also what many people understand about bitcoin.

- To really look inside bitcoin though, you need to understand that it is a decentralized system of currency, which is opposed to a central banking systems which we are using today.

- If you want to understand bitcoin in this level, then BCT is your class. You will first learn how the basic structure of bitcoin blockchain works.

- Built upon the idea of blockchain, you will also learn how bitcoin's transaction really works, what is the role of miners, how mining works, and do blockchain really provides anonymity? what is the role of community in bitcoin? Who really controls bitcoin?

- And finally it's about altcoins, which I believe is more relevant to our time - as the combined altcoins market values is on par with bitcoin. So what are they? Why are they there. The course will not cover all famous altcoins we know today, but it will give you the basics.

- I found the content of the class illuminating. And I highly recommend anyone, especially with general CS background, goes to take BCT first before you do anything related to cryptos. You will find yourself more educated than your peers in many issues, even on basic operations such as trading and mining.

- My only criticism of the course is that it is dated back in 2015. Of course, things changed dramatically last 2 years: events such as bitcoin hard forks, the rise of ethereum are all unforeseen by the lecturers. That doesn't devalue the class at all. As for me, it just gives me historical perspective of the technology.

- If you enjoy the course, go ahead to read the book by Arvind Narayanan as well, once again, it is a great intro of the subject.

That's what I have, hope my impression helps.


* In fact, you may say "Should I buy bitcoin at $?" is the most frequently asked question. But of course those type of questions are banned by our strong rules.