Systems 101

Computer Science and Computer Systems 101 Series.

Blockchain | Systems | Systems 101 | Tutorial

The Role of DEX Aggregators and Routers in Decentralized Trading
ByEric Ma Mar 17, 2025Apr 9, 2026

DEX Aggregators and Routers in Decentralized Trading Trading across decentralized exchanges requires navigating fragmented liquidity spread across dozens of protocols and blockchains. DEX aggregators and routers are the essential infrastructure that finds optimal execution paths, minimizes slippage, and protects against MEV extraction. Routers vs. Aggregators The distinction matters operationally: Routers are smart contracts that execute…

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Systems 101 | Tutorial

Understanding TPM 2.0 and Platform Configuration Registers (PCRs)
ByEric Ma Dec 14, 2024Apr 9, 2026

What is TPM 2.0? The Trusted Platform Module (TPM) 2.0 is a cryptographic coprocessor—either as discrete hardware or firmware—that provides hardware-rooted security. It’s the foundation for features like Windows Hello, BitLocker, macOS FileVault, and Linux dm-crypt integration with hardware key binding. On modern systems, TPM 2.0 is nearly universal: integrated into recent Intel (PTT), AMD…

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Blockchain | Systems | Systems 101 | Tutorial

Private Key Sharding: A Technical Guide
ByEric Ma Sep 14, 2024Apr 9, 2026

Private Key Sharding: A Technical Guide Private key sharding splits a private key into multiple parts called “shards” that must be combined to reconstruct the original key. This eliminates the single point of failure inherent in traditional seed phrase storage while maintaining on-chain simplicity. The most common implementation uses Shamir’s Secret Sharing (SSS), a cryptographic…

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Blockchain | Systems | Systems 101 | Tutorial

What is BTC SegWit and Its Impact on Transaction Fees
ByEric Ma Sep 14, 2024Apr 9, 2026

Segregated Witness (SegWit) is a Bitcoin protocol upgrade activated in August 2017 that restructured how transaction data is encoded and validated. It’s foundational to modern Bitcoin usage and essential for understanding current fee dynamics and layer 2 scaling. How SegWit Works Bitcoin transactions contain two main components: the transaction structure itself and the cryptographic signatures…

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Blockchain | Systems | Systems 101 | Tutorial

Understanding Bitcoin Transaction Structure: Legacy and Witness Versions
ByEric Ma Sep 14, 2024Apr 9, 2026

Anatomy of a Bitcoin Transaction Every Bitcoin transaction consists of two main components: Inputs (UTXOs): Unspent Transaction Outputs from previous transactions that you’re now spending. These are references to outputs you received earlier. Think of them as specific bills from your wallet you’re handing over. Outputs: The destinations and amounts for the Bitcoin. This includes…

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Blockchain | Systems | Systems 101 | Tutorial

Proving Ownership of BTC Multisig Addresses
ByEric Ma Sep 14, 2024Apr 9, 2026

Proving Ownership of BTC Multisig Addresses Proving ownership of a multisig address differs fundamentally from proving ownership of a standard single-key wallet. With multisig, there’s no single private key to demonstrate. Instead, you need to prove control over enough keys to satisfy the wallet’s m-of-n threshold (for example, 2-of-3 or 3-of-5). The Core Challenge In…

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Blockchain | Systems | Systems 101 | Tutorial

Proof of Ownership for BTC Addresses: A Detailed Guide
ByEric Ma Sep 14, 2024Apr 9, 2026

Proof of Ownership for BTC Addresses Proof of Ownership is a cryptographic method to demonstrate control over a Bitcoin address’s private keys without moving funds or exposing the key itself. It’s essential for withdrawals to new addresses, OTC trades, collateral verification, and exchange account recovery. How Digital Signatures Work The mechanism relies on public-key cryptography:…

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Systems | Systems 101 | Tutorial

A Comprehensive Guide to PGP: Technical Deep Dive
ByEric Ma Sep 8, 2024Apr 9, 2026

How PGP Works: Symmetric and Asymmetric Cryptography PGP combines symmetric and asymmetric encryption to achieve both speed and security: Symmetric Encryption: The message itself is encrypted using a random session key with an algorithm like AES-256. This is computationally fast for large files. Asymmetric Encryption: The session key is then encrypted with the recipient’s public…

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Systems | Systems 101 | Tutorial

Linear Consistency Model for Computer Systems
ByEric Ma Sep 6, 2024Apr 9, 2026

Linear Consistency in Distributed Systems Linear consistency (also called linearizability) is a formal correctness condition for concurrent systems. It guarantees that all operations appear to execute atomically in some sequential order, with each operation taking effect instantaneously between its invocation and response. In practical terms: once an operation completes and a client receives acknowledgment, every…

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Systems | Systems 101 | Tutorial

Understanding Cloud Storage Consistency Models
ByEric Ma Sep 6, 2024Apr 9, 2026

Consistency Models Cloud storage systems face a fundamental trade-off: you can’t have everything at once. The consistency model you choose directly impacts latency, availability, and how complex your application logic needs to be. Here’s what you actually need to know to pick the right one. Strong Consistency Guarantees that any read returns the most recent…

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Computing systems | Systems | Systems 101 | Tutorial

Comparing Paxos and Raft
ByEric Ma Sep 6, 2024Apr 9, 2026

Paxos and Raft: Consensus Algorithm Comparison Paxos and Raft are foundational consensus algorithms for distributed systems. Both solve the same core problem — achieving agreement across multiple nodes despite failures — but take fundamentally different approaches. Paxos Paxos operates around three distinct roles: Proposers submit values Acceptors store and respond to requests Learners observe the…

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Computing systems | Systems | Systems 101 | Tutorial

Understanding the Paxos Consensus Algorithm
ByEric Ma Sep 6, 2024Apr 9, 2026

The Paxos Consensus Algorithm Paxos is a fundamental consensus algorithm for distributed systems that guarantees agreement on a single value even when nodes fail or messages are delayed. Developed by Leslie Lamport in 1998, it remains a cornerstone for building fault-tolerant distributed systems where strong consistency is required. The Core Problem In a distributed system,…

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Computing systems | Systems | Systems 101 | Tutorial

Understanding the Raft Consensus Protocol
ByEric Ma Aug 24, 2024Apr 9, 2026

Understanding the Raft Consensus Protocol Raft is a consensus algorithm designed to be more understandable than alternatives like Paxos. It ensures a cluster of servers can agree on system state even when some nodes fail. The core insight is breaking consensus into independent, manageable subproblems rather than treating it as one complex whole. Core Subproblems…

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Systems 101

Multisig 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

Multisig Fundamentals Multisig (multisignature) is a cryptographic mechanism that requires multiple private keys to authorize a blockchain transaction. Think of it as a vault requiring two or more keys to open — no single key holder can move funds alone. How It Works A multisig wallet uses an m-of-n formula, where m is the number…

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Systems 101

Sybil Attack 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

Understanding Sybil Attacks A Sybil attack occurs when a single adversary creates many fake identities or nodes to gain disproportionate influence over a network. The name comes from the book and film “Sybil,” about a woman with dissociative identity disorder. In networking and distributed systems, it describes the same concept: one actor pretending to be…

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Systems 101

Byzantine Faults 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

Byzantine Faults in Distributed Systems A Byzantine Fault occurs when a component in a distributed system behaves unpredictably or maliciously—sending contradictory information to different parts of the system, corrupting data, or deviating entirely from the protocol. The result is potential inconsistency across the network, making consensus impossible without proper safeguards. The term originates from the…

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Systems 101

WebDAV 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

WebDAV Overview WebDAV (Web-based Distributed Authoring and Versioning) is an HTTP extension that lets you manage files on remote servers over the web. It’s built on HTTP/1.1, so it works through standard web infrastructure—firewalls, proxies, load balancers—without special configuration. Think of it as a bridge between simple HTTP file serving and full-featured version control. You…

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Systems 101

Consensus Algorithm 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

What Is Consensus? In distributed systems like blockchains, consensus is the mechanism by which all nodes agree on a single version of the ledger state. Without it, a decentralized network falls apart—you’d have conflicting transaction histories, double-spending, and no way to determine which version is authoritative. Consensus algorithms solve this by providing cryptographic or economic…

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Systems 101

Double-Spending 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

The Core Problem Double-spending is the fundamental vulnerability of digital currency: unlike physical cash, digital information can be copied. If you send me a digital file, I have it and you still have it. Money can’t work that way. Without a mechanism to prevent spending the same unit twice, the entire system collapses into worthlessness….

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Systems 101

51% Attack 101
ByEthan Ainsworth Sep 16, 2023Apr 9, 2026

What Is a 51% Attack A 51% attack happens when an entity or coalition controls more than 50% of a blockchain network’s total hash rate (in Proof-of-Work systems) or stake (in Proof-of-Stake systems). With this majority control, the attacker can: Reverse recent transactions — spend coins, then revert the transaction to regain them Block legitimate…

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