Kennidy L. Guimarães

The Hierarchical Distribution of Information

2026-06-05T00:00:00+00:00

There is a widespread belief that the greater the power concentrated in an individual, the greater the information that individual holds about the states of the system over which they exercise authority. This, however, does not correspond to observed reality; on the contrary, empirical evidence and structural analysis point to a relationship that is the inverse of this common assumption.

The Network Society: CIDR, NAT and the Collapse of End-to-End

2026-05-22T00:00:00+00:00

In the first article of the “The Network Society” series, I covered how the internet evolved from simple networks of sterile communication between themselves into Full Duplex communications, enabling active end-to-end communication through TCP/IP. In this second article, I will explain how one of the greatest limitations of this system came to be, why engineers underestimated the original calculation, and how that led to the (partial) collapse of End-to-End communication.

The Network Society: TCP/IP Protocol and the Birth of the Internet

2026-05-13T00:00:00+00:00

The internet as we know it is a tangle of protocols, requests, and methods being applied together with mathematical algorithms. In this article, I want to address the functioning of one of these protocol suites, the TCP/IP suite, and how your computer is identified on the network.

Artificial Intelligence Does Not Pay for Itself: The Structural Limits of a Trillion-Dollar Bet

2026-05-05T00:00:00+00:00

Predicting the future is, by definition, a limited exercise. I consider any forecast about what lies ahead either misleading or, at best, a rough estimate — and that is precisely the point: an estimate, no more reliable than yours, though supported by documented past events you may not be examining. Anyone who can genuinely foresee the future either lived it or has the means to force it into being. Everything else is projection.

DDD in Practice: Modeling Entities and Value Objects - Part III

2026-05-04T00:00:00+00:00

In the previous article, we dealt exclusively with Ubiquitous Language and the pain points of a multilingual system — when the goal is the exact opposite: a system where each context speaks the language of its own context. In this article, we will address precisely that. From where we left off, we could observe that an order in our pizzeria’s kitchen is a pizza order, and an order in the Fiscal domain is a fiscal document — which are entirely different things.

Universe Simulation: A Problem of Energy, Parallelism, and Coherence

2026-04-08T00:00:00+00:00

I often hear the paradox: if we are in a matrix, you would never know; you could, right now, be living inside a matrix within another matrix and never realize it. I like to argue that such an idea is mainly based on the hypothesis of absurdity, or of “ignorant scientists”; that is, we would be facing a large conglomerate of scientists who, in other words, would be ignorant regarding the nature of atoms and stars, or we would be facing a terrifying force with enough energy to sustain infinite suns and the infinity of infinity merely to observe our simplest daily activities.

Pursuit-Evasion Problem: A Probabilistic Search Analysis in a Deterministic Scope

2026-04-06T00:00:00+00:00

Imagine yourself in a dark room, as dark as it can possibly be. With you are many people — a reasonable number, perhaps fifty of them — all in a room of approximately $100\,\text{m}^2$.

How A* Uses Heuristics and Mathematics to Define the Best and Least Costly Route

2026-04-01T00:00:00+00:00

Having explained Dijkstra’s algorithm, we cannot overlook another algorithm that uses a similar system but is profoundly different: the A* algorithm (read as “A-star”). Peter Hart, Nils Nilsson, and Bertram Raphael from the Stanford Research Institute (now SRI International) published the foundational paper on this algorithm [1].

How Mathematics is Applied to Dijkstra's Algorithm to Find the Best Path Between Nodes

2026-03-26T00:00:00+00:00

You are driving through the city, need to quickly get to a meeting with your girlfriend, and certainly don’t want to seem uninterested — delays can seem unforgivable. Luckily, you can always count on a routing app like Google Maps. But how does it actually work? If you had no app, just your paper map, how would you calculate the shortest route, considering the thousands of turns, hundreds of streets, and local and global variables? It can actually be done — though you’ll still prefer to use Waze.

Critical systems and cascading failures in complex systems

2026-03-24T00:00:00+00:00

If you have developed many projects, or lived through the security bubble between 2000 and 2015, you have probably heard the terms “critical project” or “safety-critical” repeatedly. This is directly tied to the state of digital security and the digitalization process that, in my country (Brazil), was already happening en masse during that period.

DDD in Practice: From Ubiquitous Language to Bounded Context - Part II

2026-03-23T00:00:00+00:00

In the previous article, we covered several topics at once and understood why modeling a system is truly necessary — and where that need comes from. Before building, we must understand the reason for building. Now, before we type a single line of code, there is something crucial to DDD we need to grasp — something that is not exclusive to DDD, but central to Clean Architecture as a whole. It is grounded in Clean Code and in the KISS principle (Keep It Simple, Stupid). I am referring to the Ubiquitous Language — and make no mistake: this is not difficult.

DDD in practice: from problem to model - Part I

2026-03-13T00:00:00+00:00

Harder than implementing a healthy software architecture is not implementing one. That is the kind of problem that surfaces after months of work: the system that ran fine yesterday starts throwing errors and everything grinds to a halt. The problem extends beyond the technical — it strikes the financial health of the company, especially when critical services are involved. And nearly every service is critical. [1]

True Quantum Computing: An Honest Introduction to QC

2025-01-10T00:00:00+00:00

You have certainly heard the term “Quantum” applied to some product, service, or project. The problem is that this term has been used in a way completely disconnected from its real meaning — because something quantum can only truly be quantum if it deals with phenomena at a subatomic scale. Yet some marketing agents believe this term can be applied to any product, service, or project. Which is, fatally, a mistake.

Understanding the Mathematical Functioning of Hashing

2024-11-25T00:00:00+00:00

Cryptographic hash functions are a foundational primitive in modern security systems, yet their internal mathematical mechanisms are rarely examined in detail outside of academic circles. This article offers a precise, technically grounded explanation of the SHA-256 algorithm — a member of the SHA-2 family developed by the NSA and standardized by NIST. We examine its complete processing pipeline, from binary encoding and padding through block decomposition, compression rounds, and final digest construction. We further analyze the practical infeasibility of brute-force attacks against SHA-256 by comparing its key space to measurable physical constants of the observable universe. The article is intended for developers and technical readers who are familiar with basic cryptographic concepts and seek a more rigorous understanding of how hashing actually works.

The Chain Nobody Controls: How Blockchain Works: Blocks, Hashes and Mining

2023-10-16T00:00:00+00:00

Blockchain is a distributed and immutable ledger — the infrastructure that makes Bitcoin possible. In Part 1 of this series, we saw how it solves the double-spending problem. Now we go one level deeper: how this structure actually works internally, block by block, hash by hash [1].

The Chain Nobody Controls: Bitcoin as an Intangible Asset and the Double-Spending Problem

2023-10-16T00:00:00+00:00

Trust is a risk asset. Employers trust employees to perform their work; employees trust employers to pay them. Buyers trust merchants to deliver goods honestly, while merchants trust that the money they receive is legitimate and retains value. Contracts depend on courts, banks depend on governments, and society itself depends on the assumption that these systems will continue to function tomorrow as they do today.

Random Hash Cascade (RHC): A Pseudo-Random Hashing Algorithm Using Mersenne Twister and SHA-256

2023-06-07T00:00:00+00:00

Abstract

The use of pseudo-random values has become increasingly essential, being widely employed in various areas such as cryptography, security, monetization, and data analysis. This study presents the development of an algorithm in the construction phase, Random Hash Cascade (RHC), which aims to provide a satisfactory balance between security and performance. RHC utilizes the Mersenne Twister (MT) algorithm, combined with mathematical operations on arrays, to generate reliable and efficient results. It is important to highlight that, as this is a developing algorithm, caution must be exercised in its application, and complementary testing is essential to validate its effectiveness and security in different scenarios.