What to teach when teaching blockchain

What to teach when teaching blockchain

This article is part of a series of articles depicting my experience with creating and conducting an 8 week long blockchain app development course in Brazil.

 

The course as a mega structure

After I accepted to take on this challenge, the next logical course of action was to create the listof material I intended to teach the students. Originally, this list contained almost everything blockchain related – from bits, bytes and creating protocol messages all the way up to an overview of the history and politics of Bitcoin. The list was long, perhaps too long. I must admit my own limitations- I couldn’t see any realistic way to create such an extensive course by myself.

In addition, I had some doubts as to how many students can actually properly digest so much material, even when given 8 full weeks. (6 actually, if you count the time given to personal projects). I realized the list needed to be more focused – and that’s where my first major decisions were made.

 

Decision number 1: Focusing on the protocol itself. By deeply understanding the Bitcoin (and later the Ethereum) protocol, I believed the students will gain some clarity and very strong foundations upon which they can later build on and learn more extensively by themselves.

It was highly important to me to ensure they actually understand the protocol itself – how it developed, the tools it utilizes, and the logic behind choosing these specific tools and architectures and so on.

Once the students understood the intricacies of dealing with it, they will be better equipped to learn by themselves other things like how to use JS libraries in web applications; read and understand whitepapers and BIPs/EIPs, and create their own private chains and more. But how do I teach the protocol? That’s where my second decision was made.

 

Decision number 2: Bitcoin is the gold standard of blockchains and therefore, the go to chain when learning the basics of blockchains. This decision was a no brainer for me and represents a substantial chunk of my personal view on the blockchain ecosystem. The Bitcoin blockchain is the most widely used, heavily researched and extensively documented (albeit the documentation is somewhat lacking in my opinion). Every blockchain in existence this day stemmed from it and relies to a large extent on many of the concepts introduced by it.

It was clear to me that creating a blockchain course that isn’t based on the Bitcoin protocol will be a major breach of the faith the students reposed in me.

These two decisions brought with them peace of mind. Whereas before I was drowning in a pool of topics to cover – a list so long and chaotic, it was completely unmanageable, I now had a solid anchor to work with.

 

 

The four stages of mastering the blockchain

Once the list was completed, it became clear it could be divided into 4 main stages or phases:

The basics

From bit and bytes to protocol messages. The idea is that once completed, the student is able to send, receive and (maybe most importantly) parse a Bitcoin protocol message. In order to achieve this, the students will need to learn the basic mechanism of networking, create the byte code for a Bitcoin message – both payload and header, learn how to use one-way functions, hashing and how to read and understand the Bitcoin developers guide and protocol documentation.

Here, I held enlightening conversations with the students that revolved around keys. We went through the documentation together in a bid to learn about how to move seamlessly from private key to the public one and onto Bitcoin address.

Transactions

The bread and butter of the Bitcoin protocol. Now that the students have the understanding of how to work with the Bitcoin documentation, the next logical step was channeling that documentation and using it in creating transactions.

Here, the students will garner all their knowledge about bits and bytes, hashing and keys (from the previous stage) and channel it into creating the raw Bitcoin transaction. After which, they will learn about the pkScript; scripting in Bitcoin (and scripting in general) plus stack architecture and how the pkScript is executed, which by the way is also a great opportunity to start the conversation with the students about Ethereum and its virtual machine.

 

Finally, the students will go on to elucidate on what type of transactions are considered standard.

 

Blockchain architecture

After speaking with the students about all the basic components required in creating and transmitting a Bitcoin transaction, it was time to move on to talks about blocks and their architecture. I wanted them to have an understanding of what blocks really are. We were to create merkle trees (and merkle roots), blockheaders, calculate (mock) difficulty and target, and find the proper nonce. Along with that, it was also a great chance to have a chat with the students about DAG and consensus, mining algorithm, forks and altcoins.

In this phase, I was also afforded an invaluable chance to have a discussion with the students about contracts and secondary layers such as lightning network and BIPs (SegWit, addresses and other bips).

Ethereum

This is the second most predominant chain out there. It includes the wild west of consensus rules, mining algorithms and script (VM) playground. Many students want to understand how it works, and rightfully so. However, what most students want in learning Ethereum is how to actually use it – how to write smart contracts, and hence, how to use Solidity. This is where my previous decision to focus on Bitcoin as the gold standard for blockchain architecture became two opposite things; a blessing and a curse.

I wanted to spend as much time as I possibly could on Solidity, Web3 and Ethereum specific tools, and since I already spent more than half of the course talking about blockchain and Bitcoin, I was freer to talk about Solidity and web3 in this part of the course. However, a compromise was made and several unique architectural aspects of Ethereum were left out. I briefly talked about gas and the EVM by tying it to Bitcoin scripts and fees, and I glossed over block structure by simply stating that “merkle roots are also involved”. Mining and Ethereum attempts to move to POS were completely ignored – I think you get the picture.

The only architectural aspects of Ethereum I discussed in class were the ones that can be easily seen when playing with Solidity and smart contracts (Libraries and calls, Inline assembly, variables gas price, constant functions, variables scopes etc.)

 

I used this general scheme to select the topics to be covered in the Bitcoin part of the course

 

A sense of achievement

All in all, I’m quite proud of this structure and the topics it included. I found myself with a solid and detailed road map of the course. It was clear to me and to a lesser extent my students where we are now, and what is yet to come. I also hoped to use these 4 stages as the basis on which I would create semi-official certificates for my students. The idea was that every 1.5-2 weeks or so, the students did manage to achieve something very meaningful.

On completion of the first stage, the student managed to establish connection to a remote node on the Bitcoin network, and created key pairs and Bitcoin address.

On completion of the second stage, the student proved that he/she possesses a deep understanding of how Bitcoin transactions work. Things like how to hash a transaction, how to deal with TXID, how fees are determined, how (and when and where) signatures are used in the protocol and how the Bitcoin scripting language works. All of these gave the students a platform to create the bytecode for their own transactions (P2PKH and OP_RETURN).

At the time the third stage was completed, the students had managed to create their own block by creating the merkle tree and finding its root, calculating (mock) target, creating the blockheader and eventually finding the right nonce (Important note: I didn’t ask the students to create a coinbase transaction, although we did talk about it and examine its structure, but I believed adding another type of transaction will only serve to confuse them).

The final stage, the Ethereum stage, was in fact more of free working sessions. As I mentioned earlier, one of the requirements was that the students will have time to create their own dApps. Each student was working on his/her individual projects and as long as they managed to get their smart contracts to work, they managed to complete this stage.

(More details on my experience with the certification system in the coming articles).

 

 

So how did it go?

The first part of the course went rather smoothly, either because the students were still very eager to learn or because it was truly well constructed.

However, owing to some technical problems, I did not receive the certificates on time which placed me at a somewhat awkward position. Not only did I make a promise to my students that I’d give it to them, I was also quite worried that in the absence of something more tangible, they might not properly appreciate their own progress during the course.

This fear continued to be my shadow through the duration of the course as I tried to motivate my students to continue their hard and not so rewarding work. Right at the end of the course, I did manage to receive some documentation I could give my students and the response was very positive indeed. I’m now more convinced than ever that providing a proper certification at the end of each step can reduce much of the stress and hardship associated with such a demanding course. As a matter of fact, one of the major decisions I made at the end of this course was regarding certifications.

There was a major criticism I received during the course in relation to the course structure. A good number of the students, while not showing any major problem understanding the granular topic of the day and implementing the codes did have a hard time seeing the bigger picture. The structure I created aimed to look at the blockchain from a very close distance while working with some of its finest components.

I did try to encourage additional “free conversations” in class, hoping that during these less formal chats the students will utilize what we learned But soon it became clear to me that the timing of these free conversations, their length and their focus (or lack of it), was quite counterproductive. Therefore, I needed to come up with more appropriate time slots for such informal class sessions, while making sure to be well prepared with case study in case the students will not be focused. . For example, it might have been productive to try and talk about SigWit during the transactions class instead of only at the end of the Bitcoin portion of the course, even though the students didn’t yet learn about merkle trees, blocks architecture and BIPs.

The students were vocal about their desire for me to focus more on the big picture. This was in addition to some external pressure placed on me to start working with the students on their own personal projects. All of these led me to the production of some minor (yet quite meaningful) changes to the structure, mid – course. Basically, the border between the third stage (Blockchain architecture) and the fourth (Ethereum) was less strict than I wanted it to be.

It is true I already planned to use the third stage as a transition stage (as mentioned above, a substantial part of the Ethereum architecture was glossed over by comparing it to the Bitcoin blockchain). I did plan to talk about Ethereum quite extensively at this point (Ethereum was supposed to be mentioned first at the end of the second stage- transactions stage- right when the students learned some standard pkScripts). I still wasn’t well prepared with a suitable road map to make this diversion from the predefined curriculum.

The final result was that the transition from Bitcoin to Ethereum was lacking at best, if not somewhat confusing. This experience, while being somewhat hard in real time, did help to solidify my own confidence in the structure of the course – at least in its higher level and I’m much less inclined to perform similar deviations in future courses.

Another veritable source of confidence is the progress many students showed. A small, yet substantial, part of the class came on board with little to literally zero experience in programming and blockchains. Yet, by the end of it, I did witness some highly impressive progress in their abilities and understanding while the more advanced students also managed to create some impressive codes, smart contracts and even to construct a few apps. Ultimately at the end of the day, that’s what matters the most.

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