Textos · Arkhatic

Mergulhos profundos nas
decisões técnicas por trás do meu trabalho.

Sistemas de engine, pipelines de segurança, síntese de áudio, análises de game design, investigações de incidentes. Alguns posts técnicos são detalhados o bastante para eu reconstruir o projeto a partir deles — e é essa a ideia!

17 entradas·RSS ↗
Segurança
18 de julho de 2026
12 min de leitura

A frota que não existe: um app na Play Store, um CNPJ de 3 semanas e o Ponzi dos robotáxis mirando o Brasil

O Taxinexo vende a brasileiros uma cota de uma frota de táxis autônomos que roda sozinha por Nova York e paga 90% ao mês. A frota é uma folha de sprites, as corridas são um cron job, e a empresa por trás é uma varejista de eletrônicos com 3 semanas de vida num escritório virtual na Avenida Paulista. As evidências, a aritmética e a linha do tempo do colapso. Constatações e raciocínio, não um guia de derrubada.

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Sistemas de engine
16 de junho de 2026
22 min de leitura
EN

How direct drive force feedback actually works

Direct drive does not add feel. It removes the mechanical filters that gear and belt reduction stages impose. A trace of one number, from the tire model to torque at the rim.

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Segurança
15 de junho de 2026
18 min de leitura
EN

Capabilities over signatures: the design behind a .blend inspector, and the provenance layer that sidesteps the fight

The technical companion to The weight of a hyphen. Two questions you can ask of a file that runs itself, what will it do and who made it, decompose into a detection problem you can only draw and a provenance problem you can win. The capability model that keeps a static inspector from drowning in false positives, the four-move evasion arms race and the four answers, and the signing math that makes a pirated copy fail by arithmetic. Architecture and decisions, not source.

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Segurança
14 de junho de 2026
16 min de leitura
EN

The weight of a hyphen: a lookalike domain, a self-running file, and the inspector I built to catch it

A friend's Blender community was bleeding Discord accounts, and one of his domains had started serving malware. The domain was never his, the attack rode a single missing hyphen, and the real leak was a thousand endpoints. The investigation, the file format that runs itself, and the tool I built so Blender stops asking you to trust blind. Narrative and decisions, not a playbook.

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Segurança
24 de maio de 2026
31 min de leitura
EN

Calibration as infrastructure: building a detonation lab

Six stages, four tensions, and the engineering decisions that determine whether a detonation lab earns its keep. How specimens enter, deploy, detonate, are observed, are analysed, and are archived, with notes on the tradeoffs that recur at every stage and the boring parts that compound over years. Architecture and decisions, not code. Engineering register, not academic.

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Hardware
22 de maio de 2026
20 min de leitura
EN

The thermal wall: how phones and handhelds spend the same watt-budget two different ways

Mobile silicon stopped being transistor-limited and became heat-limited. This is a deep dive on what actually moves the heat (graphite, vapor chambers, fans) and the software that decides who gets throttled first, read across two device classes that answer the same thermal equation in opposite directions.

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Segurança
20 de maio de 2026
41 min de leitura
EN

Below the burn line: the architecture of operator infrastructure

Three tiers, four attribution surfaces, and the analyst posture they are all calibrated against. Why operator infrastructure decomposes into long-haul, redirector, and staging tiers, what discipline each tier requires across DNS, TLS, behavioural, and financial surfaces, and how the operator's own workstation becomes the single point of correlation that none of the tier discipline addresses. Architecture and decisions, not configuration. Methodology, not playbook.

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Composição
19 de maio de 2026
10 min de leitura
EN

A signal teardown of "The World That Bears My Name"

The technical companion to the composition writeup. Same track, opposite lens: what the rendered audio measures, why a beat tracker reads the meter wrong, how the dynamics are engineered across four minutes, and the one master decision the numbers say I got wrong. The why lives in the other post; this is the how.

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Composição
19 de maio de 2026
14 min de leitura
EN

The World That Bears My Name: writing the voice of the one who burned the world

Ashlight's main theme is sung from inside the error the whole game is about not repeating. This is what the song means, why the melody climbs while everything beneath it falls, and how an arrangement learns to confess.

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Segurança
16 de maio de 2026
34 min de leitura
EN

Building the inverse: the design decisions behind a three-layer dropper

The same architecture from the other direction. Why a layered .NET dropper has three layers and not two or four, what each layer is solving for, and which defender assumptions the design quietly presupposes. A composite reference design drawn from the artefact dissected in Three layers deep and adjacent commodity infostealer campaigns through 2024 and 2025. Architecture and decisions, not source. Companion to the reverse-engineering writeup.

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Segurança
13 de maio de 2026
21 min de leitura
EN

Three layers deep: reverse-engineering a .NET RAT dropper

Three layers down into a 1.1 MB junk-padded batch script: from cmd.exe macro obfuscation through a PowerShell shellcode loader to a Donut-packed implant living inside explorer.exe. The dropper hides its payload steganographically in 3,500 lines of comments, renames powershell.exe to evade name-based detection, and uses a 7-byte memory marker for cross-reboot idempotence. Companion to the incident writeup.

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Segurança
12 de maio de 2026
14 min de leitura
EN

The cutest trap on the internet: weaponizing Google's child-safety system as a kill switch

A fake Minecraft launcher infected my friend α's machine on a Tuesday evening. By morning, an operator had used the stolen access to upload triggering content to α's Google account, log out, and let the platform's own automated child-safety detector erase the witness. The malware is the carrier; the kill switch is the story. The technical reverse-engineering lives in the companion post.

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Sistemas de engine
11 de maio de 2026
10 min de leitura
EN

Audio as a gameplay pillar: why Ashlight runs on FMOD instead of Unity's AudioSource

Ashlight's audio isn't decoration, it's a core gameplay pillar that has to deliver frame-aligned legendary telegraphs, an AI hearing system that reads player footsteps, and a Lucidity scheduler that fires phantom cues without ever lying to the player during real combat. Here's the middleware decision, the 10-RTPC contract that binds Unity to FMOD, and why the most interesting audio code in the game lives outside our codebase.

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Fullstack
11 de maio de 2026
8 min de leitura
EN

Picking RTDB for the auction hot path: three reasons and three regrets

Project Sato's hot path needs sub-100ms latency, atomic bid ordering, and listener cost that doesn't blow up under load. RTDB delivers two of three; Firestore delivers none. Here's why I split them, and what the split costs.

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Sistemas de engine
8 de maio de 2026
6 min de leitura
EN

Building a real-time Saturn ephemeris in React Three Fiber

How I rebuilt a Wallpaper Engine's Saturn simulation as the hero element of a portfolio site: Keplerian propagator for the moons, procedural ring shader, and ~5000 ring particles.

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Sistemas de engine
22 de abril de 2026
8 min de leitura
EN

Ashlight: building a horror engine layer on top of Unity

The systems work behind Ashlight: a custom render feature stack, dynamic dread budget, and the editor tooling that made it possible to ship without burning the team out.

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Play · Crítica
20 de abril de 2026
17 min de leitura
EN

Minecraft, 5.2 / 10: separating the product from the phenomenon

Reviewing Minecraft in 2026 as a commercial product instead of a cultural phenomenon, held against the genre specialists that overtook it (Terraria, Factorio, Valheim, Dwarf Fortress) and against Mojang's own resources. The honest score is well below consensus, and the gap between best and important is the most interesting thing about it.

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