File type detection vs antivirus: what each one actually tells you
A detector tells you what a file is. An antivirus tells you whether it is known to be bad. They answer different questions, and confusing them leads to false confidence in both directions.
securitydetectionmalware.DS_Store, Thumbs.db, desktop.ini: the hidden files your OS leaves everywhere
Every folder you copy between computers picks up invisible files you didn't create. What each one is, whether deleting it is safe, how to stop them being made, and the one that can leak information from a web server.
how-tofilesmacoswindowsWhat is a .dat file? (It depends, and here's how to find out)
DAT is not a format. It is a label programs use for 'data', which is why a .dat file can be an email attachment, a Windows registry hive, a video or a game save. How to tell which one you have.
how-todetectionfilesIs this attachment safe? A 60-second check for any file
Most malicious attachments are caught by three questions that take less time than opening the file. The questions, the file types that deserve them most, and the one check that works for everything.
securityhow-toemailFLAC vs MP3 vs AAC vs Opus: lossless and lossy audio, explained
What lossless actually means, when it matters, which lossy format to pick for a phone or a car, and the conversions that make sense. With the one rule that saves people the most disk space.
formatsaudiocomparisonWhy iPhone photos won't open on Windows, and every way to fix it
HEIC is a better format than JPEG and a worse experience on a PC. What the format is, why Windows balks, the free fix, and how to stop the problem at the source.
how-toimageswindowsiphoneMagic bytes: how to read a hex dump and identify any file
The first 16 bytes of a file usually say what it is, if you know how to read them. A hands-on introduction to hex dumps, file signatures and the handful of patterns worth memorising.
detectionhow-tolow-levelHow to open a file with no extension
A download named 'attachment', a file called 'data', a recovered file with a number for a name. Here is how to find out what it is in under a minute, on any operating system, and what to do next.
how-todetectionfilesPNG vs JPEG vs WebP vs AVIF: choosing an image format in 2026
Four formats cover almost every image on the web, and each one wins somewhere. A practical guide to which to use for photos, graphics, screenshots and logos, with the conversions that make sense.
formatsimagescomparisonwebMKV vs MP4 vs WebM: which video container should you use?
Three containers, three sets of trade-offs. When each one is the right choice, why your TV plays one and not the other, and how to convert between them without losing quality.
formatsvideocomparisongzip vs zstd vs xz vs lz4: picking a compressor in 2026
Four single-file compressors, four very different trade-offs between speed and size. Which to use for backups, builds, logs and distribution, with real numbers and the commands.
formatscompressioncomparisonlinuxHow Magika AI detects mislabeled files (and why extensions lie)
Filename extensions are user-provided metadata - they can be wrong, missing, or actively deceptive. Here's how a small deep-learning model figures out the truth from a few hundred bytes.
magikaaisecurityfile-formatsPDF vs DOCX vs ODT: when each format wins
The three dominant document formats look interchangeable until you actually try to do something with them. Here's a practical comparison.
formatsdocumentspdfdocxodtDetecting disguised malware by content, not extension
Renaming a binary doesn't change what it is - but most filters never look past the extension. A practical guide to content-based defense.
securitymalwaredetectiondefenseA practical guide to ZIP, 7Z, RAR, and TAR
Four archive formats that look interchangeable until you ship one across platforms. Here's when to use each, and how to tell them apart from the bytes.
formatsarchivescompressionReading binary files: ELF, Mach-O, and PE explained
The three executable formats that run almost every program on every desktop OS. A guided tour for people who want to know what's really inside.
formatsbinarieselfmachopelow-levelWhy MIME types alone aren't enough
The browser tells you what it thinks a download is. The server told the browser what to think. Neither of them looked at the bytes. Here's why that's a problem.
securitymimewebdetection