wtf is mifareclassictool?

MIFARE Classic Tool (MCT) is a free Android app that lets you read, write, clone, and analyze MIFARE Classic RFID tags, the small, chip-based cards and fobs commonly used for building access, public transit, and other RFID-based systems. You tap a tag against your phone's NFC reader, and the app shows you the raw data stored on it, lets you edit that data, write it to another tag, or reset a tag to its factory state. It's available on Google Play, F-Droid, and as a direct APK download. To use it, you need an Android phone with NFC hardware that supports MIFARE Classic (some phones don't, due to their NFC chip). You also need the cryptographic keys for the specific tag you want to read. The app can't crack or hack these keys, you have to obtain them through other tools or already know them. Once you have keys, you put them in a text file, and the app tries each key against every section of the tag to read as much data as possible. All data is shown and entered as raw hexadecimal numbers, so some familiarity with hex is expected. The app is built for people who already have at least a basic understanding of MIFARE Classic technology, think security researchers, hobbyists, or anyone who works with RFID access systems and wants to inspect or back up what's stored on a card. For example, if you manage building access cards and want to clone one to a spare, or if you're studying how a particular tag is structured, this tool gives you direct, low-level access to the data. It also supports special "magic" tags that allow writing to normally read-only areas, enabling fully correct clones. A few notable tradeoffs: the app deliberately avoids brute-force attacks (too slow given the protocol) and stays focused on raw data rather than offering polished workflows for everyday tasks like saving a URL to a tag. It's open source under the GPLv3, originally developed in 2012/2013 by Gerhard Klostermeier in cooperation with SySS GmbH and Aalen University.