The MIFARE Classic is the pioneer of contactless cards from NXP Semiconductors: launched in the 1990s and first produced by Philips Semiconductors, it opened the era of contactless badges and tickets in public transport, access management, ticketing and loyalty. Compliant with the first levels of the ISO/IEC 14443A standard but built on a proprietary protocol, it organizes its 1 or 4 kB memory into key-protected sectors, encrypted with the Crypto1 algorithm. It is now replaced by the MIFARE Classic EV1; its compatibility with smartphones is real but partial, and detailed below.
Information
| Manufacturer | NXP Semiconductors |
| Family | MIFARE Classic (first generation) |
| References | MF1ICS50 (1 kB) and MF1ICS70 (4 kB) |
| Standard | ISO/IEC 14443A (levels 1 to 3) |
| NFC Forum type | None (proprietary NDEF format through the MAD) |
| Operating frequency | 13.56 MHz |
| Data rate | 106 kbit/s |
| Unique identifier (UID) | 4 bytes (32 bits), factory programmed |
| Encryption | Crypto1 (proprietary), 48-bit keys A and B per sector |
| Operating distance | A few centimeters (up to 100 mm depending on the antenna) |
| Data retention | 10 years |
| Write endurance | 100,000 cycles |
| Memory | 1 or 4 kB depending on the version |
Memory
The memory of the MIFARE Classic is divided into sectors of 16-byte blocks: 16 sectors of 4 blocks on the 1K version; 32 sectors of 4 blocks then 8 sectors of 16 blocks on the 4K version. Each sector ends with a configuration block (the sector trailer):
| Area | Content | Access |
|---|---|---|
| Block 0 (sector 0) | Serial number and manufacturer data | Read only, set at the factory |
| Data blocks | 16 bytes each; possible value blocks for counters and balances | Read / write according to the sector's access bits |
| Sector trailer (last block of each sector) | Keys A and B, access bits | Governs the sector's read and write rights |
Once the configuration blocks are deducted, the 1K version offers 752 usable bytes and the 4K version 3,440 bytes. Used as an NFC tag, the proprietary MAD format (MIFARE Application Directory) makes it possible to host an NDEF message representing around 700 URL characters on the 1K, and far more on the 4K; reading this NDEF nevertheless depends on the device's compatibility, detailed below.
Features & security
- Per-sector authentication: each sector is protected by two 48-bit keys (key A and key B) verified through a three-pass mutual authentication following the ISO/IEC 9798-2 scheme; the access bits define, key by key, the allowed operations (read, write, increment, decrement), with a key hierarchy suited to multi-application schemes.
- Crypto1 encryption: exchanges are encrypted with the proprietary Crypto1 algorithm. Designed in the 1990s, it no longer meets current standards: its weaknesses have been publicly documented since 2008, and the security of a deployment should no longer rely on it alone.
- Value blocks: a block can be formatted as a signed value with a control copy; the increment, decrement and transfer commands execute with an anti-tearing mechanism, the historical toolkit of ticketing.
- 4-byte identifier: the 32-bit serial number, written into the manufacturer block, identifies each card; as the worldwide 4-byte range has been exhausted, identifiers are no longer guaranteed unique, one of the reasons behind the move to the EV1 version and its 7-byte UID.
- Fast transactions: a complete ticketing transaction executes in less than 100 ms, with the card able to remain in the wallet, even among coins: the asset that made its success at the gates.
- The MIFARE legacy: the de facto standard for contactless badges and tickets, the Classic benefits from an unmatched ecosystem (readers, encoders, cards) that explains its massive presence in existing fleets.
Production has shifted to the MIFARE Classic EV1, which replaces all previous generations; for any new project, NXP recommends the MIFARE DESFire Light. The chip existed in two capacities (MF1ICS50 for 1 kB, MF1ICS70 for 4 kB), carried over identically in the EV1 version.
Compatibility
The MIFARE Classic relies on NFC-A technology (ISO/IEC 14443A), but its proprietary protocol places it outside the tag types standardized by the NFC Forum: compatibility therefore depends on the device's NFC controller. On Android, models equipped with an NXP controller read and write the chip without restriction with NFC Tools; others may be limited to reading the UID. On iPhone, NFC Tools is partially compatible: you need to enable the "compatibility" option in the app settings (iPhone 7 and later, on iOS 15.6 or later).
With NFC Tools, the MIFARE Classic chip supports, depending on the device, reading technical information as well as reading and writing NDEF records on cards formatted with the MAD. Managing the keys and access bits requires specialized encoding through the chip's dedicated commands. The list of compatible models is available in the article on compatibility.
MIFARE Classic vs MIFARE Classic EV1
| Chip | Memory | Identifier and security | Typical use |
|---|---|---|---|
| MIFARE Classic | 1 or 4 kB | 4-byte identifier, Crypto1 | First generation, historical fleets |
| MIFARE Classic EV1 | 1 or 4 kB | 7-byte UID, Random ID, originality check | The current version, for all fleets |
Both generations share the memory, the protocol and the Crypto1 cipher: every MIFARE Classic card sold today is an EV1, which brings the 7-byte UID (in response to the exhaustion of 4-byte identifiers), the Random ID, the originality check and doubled endurance. For a new secure deployment, NXP recommends the MIFARE DESFire Light; for a consumer tag, the NTAG213 and NTAG216 guarantee compatibility with all smartphones.
Frequently asked questions
How much data can be stored on a MIFARE Classic?
1 kB or 4 kB depending on the version, i.e. 752 and 3,440 usable bytes once the configuration blocks are deducted. In the MAD format, the NDEF message represents around 700 URL characters on the 1K version.
Is the MIFARE Classic still secure?
The proprietary Crypto1 cipher dates from the 1990s and its weaknesses have been publicly documented since 2008: confidentiality and anti-cloning should no longer rely on it. The chip remains suitable for non-sensitive uses and existing fleets; for security, NXP recommends the DESFire Light, and the DESFire EV2 and EV3 offer certified AES authentication.
Is the MIFARE Classic compatible with iPhones?
Partially. NFC Tools is partially compatible: you need to enable the "compatibility" option in the app settings (iPhone 7 or later on iOS 15.6 or later).
Can a MIFARE Classic be protected against rewriting?
Yes: the access bits of each sector can forbid writing, a protection reversible by the key holder, or permanent if the access bits lock their own modification. There is no global OTP bit as on NTAG chips.
Useful links
