A blockchain is, at its core, a data structures problem. Strip away the economics and the hype and what remains is a singly linked list whose "pointers" are cryptographic hash digests rather than memory addresses, with each node (a block) carrying a tree of transactions summarized by a Merkle root. The structural choices are what produce the properties people care about: because every block header contains the hash of the previous header, altering any historical transaction changes that block's hash, which invalidates every link downstream. Immutability here is not a policy or a promise — it is a consequence of how the structure is wired together.
In this course, blockchain serves as a case study in composition. You have already studied linked lists, hash functions and hash tables, and binary trees in isolation; here you see them stacked so that each one does a specific job. Hashing provides a fixed-size fingerprint and collision resistance. The Merkle tree lets a verifier confirm that a single transaction belongs to a block using only O(log n) sibling hashes instead of downloading the whole block. The block header bundles the metadata (previous hash, Merkle root, timestamp, nonce, difficulty) that makes validation cheap. Distribution and consensus then decide which chain the network accepts when two valid chains exist.
As you watch the videos below, keep a running list of questions: Which structure is being used, what operation does it make fast, and what does it cost? Where does a hash act as an identifier versus as an integrity check? How does a Merkle proof differ from re-hashing an entire block? Note that these videos come from industry and educational channels rather than an algorithms course, so you may need to translate their vocabulary back into the data structures terms we use in lecture.
This video walks through the layered view of blockchain systems — Layer 0 (the underlying network and interoperability infrastructure), Layer 1 (the base chain where blocks, consensus, and the ledger live), Layer 2 (scaling solutions built on top), and Layer 3 (applications). Based on its title and description, it is a whiteboard-style conceptual overview rather than a code walkthrough, and it situates the block-and-chain data structure within the larger system that surrounds it.
It gives you the vocabulary and system context needed before drilling into structures, and it makes clear that the distributed ledger and consensus mechanism are properties of a specific layer rather than of the chain structure itself — directly supporting the "Distributed Ledger and the Role of Consensus" subtopic.
A short, focused explanation of what a hash is in a blockchain context, aimed at people learning blockchain development and smart contracts. Expect coverage of what a hash function does, the properties that make it useful (deterministic output, fixed length, infeasibility of reversing or forging), and how hashes are applied in blockchain systems.
Chainlink is a well-known blockchain infrastructure producer, and at under five minutes this is a tight, accurate treatment of the single mechanism that makes every other guarantee in the topic work — the integrity mechanism behind linked blocks, Merkle roots, and immutability.
A fundamentals lecture that, per its own tags, covers Merkle trees, types of blockchains, use cases, and blockchain limitations. The longer running time allows it to connect the internal structure of a block to broader questions about where blockchain is and is not an appropriate design choice.
It is the only one of the three to address Merkle trees explicitly, and its attention to limitations and trade-offs matches the course's emphasis on evaluating structural design decisions rather than just describing them.
Together these videos map onto MO1 and MO4. The Chainlink video supplies the cryptographic hashing layer, the fundamentals lecture adds Merkle trees and the trade-offs and limitations of the design, and the layers video places the chain structure inside the distributed, consensus-driven system that gives it meaning — collectively letting you explain how linked structures, hashes, and trees compose into immutability and transaction verifiability (MO1). The discussion of layers, use cases, and limitations also feeds MO4 by modeling how to identify which structures a real platform uses and what those choices cost. The graph-focused outcomes (MO2, MO3) and the integrative design task (MO5) are addressed by other materials in this module; use these videos as the concrete worked example you draw on when justifying structure selection later.
These videos were chosen from YouTube on October 2, 2026. Each has captions; the player turns them on. Videos on YouTube can be changed or removed — if one no longer plays, tell your instructor. If a player does not appear, use its Watch on YouTube link.