Whether you're a curious hobbyist looking to understand how your office access card works or a professional security researcher auditing a system, MIFARE Classic Tool is an indispensable, open-source, and privacy-respecting utility that puts the power of RFID analysis directly into your pocket.
: Decodes, encodes, and manipulates MIFARE Classic value blocks (often used for credit/counters). Technical Requirements
Mifare Classic Tool 2.3.1 offers a range of features that make it an essential tool for working with Mifare Classic RFID cards. Some of the key features include:
is a specialized Android application designed for low-level interaction with MIFARE Classic RFID tags. While newer versions like 4.3.1 are currently available on platforms like Google Play and F-Droid , many users specifically seek version 2.3.1 or similar legacy builds for compatibility with older Android hardware or specific firmware environments. Core Features of MIFARE Classic Tool mifare classic tool 2.3.1
Additional features include calculating Block Check Characters (BCC), formatting a tag back to its factory state, writing the manufacturer block (block 0) on special "magic tags," and using external NFC readers like the ACR122U for devices with incompatible internal hardware.
When a MIFARE Classic block is used as a Value Block, its 16 bytes follow a specific format for data integrity: | Byte Position | Content | Description | | :--- | :--- | :--- | | 0 - 3 | 4-byte Value | Signed integer (least significant byte first) | | 4 - 7 | 4-byte Complement | Bitwise complement of the value | | 8 - 11 | 4-byte Duplicate | Duplicate copy of the value | | 12 | 1-byte Address | Often used as a storage address (typically 0x00) | | 13 - 15 | 3-byte Trailer | Unused in standard value blocks (set to 0x00) | Data adapted from .
Mifare Classic Tool 2.3.1 is a software application designed to work with Mifare Classic cards, which are a type of contactless smart card that uses a 13.56 MHz radio frequency to communicate with readers. The tool allows users to read, write, and manipulate data on Mifare Classic cards, making it an essential utility for developers, engineers, and technicians working with Mifare Classic technology. Whether you're a curious hobbyist looking to understand
MIFARE Classic Tool 2.3.1 is a specialized Android app that turns a mobile device into a portable RFID reader and writer. It interacts with NXP MIFARE Classic RFID tags, which are commonly used in public transport ticketing, access control systems, and loyalty cards.
Select the backup file of the original card you just saved.
The built-in diff tool highlights differences between two saved tag files. This helps you isolate which specific hex blocks change when a card is swiped or updated. Understanding MIFARE Classic Architecture Some of the key features include: is a
The relevance of MCT 2.3.1 is a direct consequence of NXP Semiconductors’ design flaw in the MIFARE Classic (MF1ICS50). The CRYPTO1 cipher, though robust against brute force attacks in 1994, is susceptible to a keystream recovery attack. MCT 2.3.1 automates this vulnerability by requesting the card to encrypt known plaintext (e.g., a zero-block). When the card returns the ciphertext, the XOR differential reveals the keystream, effectively breaking the sector’s security. This version is particularly dangerous because it removes the technical barrier to entry; a security guard, a disgruntled tenant, or a curious student with a $2 NFC tag can now execute attacks that once required a Proxmark III, a $300 device.
MIFARE Classic relies on a proprietary stream cipher called CRYPTO1. Over time, cryptographic vulnerabilities have been discovered in CRYPTO1, making these chips susceptible to various attack vectors like nested or hardnested attacks. Key Features of MCT Version 2.3.1
The fourth block of every sector (Block 3, 7, 11, etc.) is the "Sector Trailer." This block contains Secret Key A, the Access Bits (which define read/write permissions), and Secret Key B.