RFID Cards
The MIFARE Classic Card is an ISO 14443-compliant contactless smart card. Introduced in 1994, it helped start the contactless card era and paved the way for a wide range of applications. MIFARE Classic EV1 is the current version of the product family and suits transportation, hospitality, event management and corporate access.
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The MIFARE Classic has remained a staple in the RFID industry for many years.
Sectors and blocks suit existing MIFARE Classic systems. Confirm that the reader and its software explicitly support Classic; a 13.56 MHz frequency rating alone does not establish compatibility.
The MIFARE Classic card is now used in virtually every corner of the world.
| Item | MIFARE Classic Card |
| Material | PVC, RPVC, PET, PETG, ABS, WOOD |
| Chip | MIFARE S50 / MIFARE S70 |
| Frequency | 13.56MHZ |
| Color | Customizable |
| Size | CR80 (85.5*54mm) or customize |
| Reading distance | 2-10cm depending on readers |
| Write Endurance | 200,000 times (Classic EV1; original chips rated 100,000) |
| Working Temperature | -40°C to 65°C |
| Data Retention Time | 10 years |
| Printing Options | CMYK full color, Pantone, digital printing, Silk-screen printing, UV Printing, etc. |
| Crafts Available | number printing, Laser Engraving, DOD, Bar code, QR code, magnetic stripe, encoding, etc. |
1, Experienced manufacturer: MIFARE Classic cards produced in our factory in Shenzhen for integrators and distributors worldwide.
2, Full printing and finishing: offset, silk-screen, UV and digital printing, laminated and finished in our factory.
3, Extensive Personalization Options: Offering a variety of customization options, including metallic backgrounds, laser engraving, barcodes, QR codes, magnetic stripes, and more.
4, Stable quality, reliable lead times: our own production, planned around your quantity and specification, with in-house quality control before dispatch.
MIFARE Classic is a contactless smart card IC family from NXP, introduced in 1994 (by Mikron, later part of Philips and now NXP). The chip uses the ISO/IEC 14443 Type A air interface, parts 1 to 3, with the Classic command set and Crypto-1 authentication rather than the ISO 14443-4 protocol layer used by DESFire. Memory is a fixed grid of sectors and blocks with two keys per sector. Existing access-control, hotel and ticketing systems may specify Classic, but support must be confirmed for the exact reader, firmware and card format.
| MIFARE Classic 1K (S50) | MIFARE Classic 4K (S70) | |
| Current part | MF1S50 (Classic EV1 1K) | MF1S70 (Classic EV1 4K) |
| EEPROM | 1024 bytes | 4096 bytes |
| Layout | 16 sectors × 4 blocks × 16 bytes | 32 sectors × 4 blocks + 8 sectors × 16 blocks |
| User data (approx.) | 752 bytes | 3440 bytes |
| Keys | One 16-byte trailer per sector: 6-byte Key A, 3 access-condition bytes, 1 general-purpose byte and 6-byte Key B | Same, 40 sectors |
| UID | 4-byte (NUID) or 7-byte | 4-byte (NUID) or 7-byte |
| Typical use | Access control, hotel keys, membership, single-purpose ticketing | Multi-application campus and city cards, transport with several products, systems that log data on the card |
Almost every access-control and hotel-lock system uses 1K; a door credential needs only a few bytes. 4K is specified when several independent applications share the card or when the system stores transaction data on it. If your integrator’s specification names a chip (S50 or S70, MF1S50 or MF1S70), order that one. Our MIFARE 4K card page covers the 4K version in more detail.
The chips in production today are the Classic EV1 generation (MF1S50yyX and MF1S70yyX). They are functionally the same as the original Classic chips, with a higher rated write endurance and a choice of UID length: the 4-byte non-unique ID (NUID) that older systems expect, or a 7-byte UID that is guaranteed unique. Most current readers accept both, but some older controllers and hotel locks read only the first four bytes, so a system that enrols cards by UID should be tested with a sample before a large order. Tell us which UID length the system was built for and we supply the matching chip.
Classic memory is a fixed grid. A 1K chip is 16 sectors, each of 4 blocks of 16 bytes, so 1024 bytes in total. The last block of every sector is the sector trailer; the blocks before it hold data. Sector 0, block 0 is the manufacturer block, which carries the UID and NXP production data and is permanently locked on genuine NXP silicon. That leaves roughly 752 usable data bytes on a 1K once the trailers and the manufacturer block are subtracted, which is why almost every access system uses the far larger 4K only when it has to.
| MIFARE Classic 1K (S50) region | Layout | Contents |
| Sector 0, block 0 | 16 bytes | Manufacturer block: UID, check byte, NXP data; read-only on genuine chips |
| Sectors 0–15, data blocks | 3 blocks × 16 bytes per sector (2 in sector 0) | User data, or a value block for a counter or purse |
| Sectors 0–15, block 3 | 16 bytes per sector | Sector trailer: Key A, access bits, general-purpose byte, Key B |
| Total | 16 sectors × 4 blocks × 16 bytes = 1024 bytes | ≈ 752 bytes usable for data |
The 4K chip keeps the 16-byte block but changes the sector sizes. Sectors 0 to 31 are small, four blocks each, exactly like the 1K; sectors 32 to 39 are large, sixteen blocks each. The addressing therefore jumps from four-block to sixteen-block sectors part way through the map, which issuance scripts must account for. A 4K holds 4096 bytes and about 3440 usable data bytes across its 40 sectors.
| MIFARE Classic 4K (S70) region | Layout | Contents |
| Sectors 0–31 | 4 blocks × 16 bytes = 64 bytes each | 3 data blocks + 1 sector trailer (sector 0 block 0 is the manufacturer block) |
| Sectors 32–39 | 16 blocks × 16 bytes = 256 bytes each | 15 data blocks + 1 sector trailer |
| Total | 40 sectors, 4096 bytes | ≈ 3440 bytes usable for data |
Two keys guard every sector. The trailer stores a 6-byte Key A, three access-condition bytes (with an inverted copy for tamper detection), one free byte, and a 6-byte Key B. Access bits decide, per block, which key may read, write, increment or decrement. A common pattern makes Key A a read key held by many field readers and Key B a write key held only at the personalisation station, so a leaked Key A exposes read access to one sector and nothing more. Cards ship with the transport configuration, both keys all FF, so an integrator writes its own keys and access bits during personalisation. Set the access bits incorrectly and a sector can be locked so that no key will ever write to it again, which is the most common first-time personalisation error.
| Sector-trailer field / value block | Bytes | Function |
| Key A | 6 (bytes 0–5) | Never read back over the air; authenticates according to the access bits |
| Access bits | 3 (bytes 6–8) + inverted copy | Map read / write / increment / decrement of each block to Key A, Key B, both or neither |
| General-purpose byte | 1 (byte 9) | Free byte in the trailer, sometimes used for a sector version tag |
| Key B | 6 (bytes 10–15) | Optional second key; readable in the trailer only if the access bits permit it |
| Value block | 4-byte signed value stored three times (bytes 0-3, inverted in 4-7, repeated in 8-11) + a 1-byte block address stored four times in bytes 12-15 as adr, /adr, adr, /adr | Supports atomic increment, decrement, restore and transfer for counters and closed-loop purses |
Value blocks are why canteen, vending and library systems ran on Classic for years: the redundant layout lets an increment or decrement survive a card leaving the field mid-write, which a plain data block cannot. None of this structure is secret; the security rests entirely on the sector keys and the cipher that protects them.
Classic protects its sectors with Crypto-1, a proprietary stream cipher with a 48-bit key, run over a three-pass authentication before any block can be read or written. Crypto-1 was kept secret for over a decade, but secrecy was the only thing holding it up. In December 2007 Karsten Nohl and Henryk Plötz presented a partial reverse-engineering of the cipher from the silicon at the Chaos Communication Congress; in 2008 researchers at Radboud University Nijmegen completed the reverse-engineering and published practical key-recovery attacks. Later work added the nested attack (which recovers the remaining sector keys in seconds once one key is known), the darkside attack (which recovers a first key from a card with default weaknesses), and the hardnested attack (which defeats the hardened Classic EV1 silicon that closed the original nested weakness). All three are implemented in free, open-source tools that run on inexpensive readers.
The practical consequence is simple and permanent: the sector keys of a Classic card can be recovered by anyone with brief physical proximity and commodity equipment, the card can then be read in full, and its contents can be written to a blank card. Crypto-1 cannot be patched to be secure. Treat MIFARE Classic as a convenience credential, not a security one — fine when the card merely names a holder that a back-end verifies, unsuitable as the sole protection for stored value, door access that must resist cloning, or anything carrying personal data. NXP no longer recommends Classic for new secure systems and offers MIFARE Plus as the drop-in AES upgrade and MIFARE DESFire for new high-security designs.
Where an installed base keeps a system on Classic for now, these measures bound the damage without pretending the card is secure:
Classic remains the right order when the installed readers and locks are Classic-only, when the card only carries an identifier that the back-end verifies, or when the risk of cloning is low and the cost per card matters more, which covers most hotel key cards, gym memberships, visitor badges and event credentials.
MIFARE Classic is an NXP product, but the 13.56 MHz market also carries compatible silicon from other makers — the Fudan FM11RF08 is the most common — that implements the ISO 14443-3A layer and the Crypto-1 command set closely enough to work in many Classic readers. Externally these parts often present the same ATQA and SAK values as a genuine chip, so a reader that only checks those cannot tell them apart. They are not identical, though: behaviour around UID writability, edge-case commands and anti-counterfeit features differs, and in August 2024 the security firm Quarkslab publicly disclosed an undocumented backdoor authentication key in the Fudan FM11RF08S (with an older key in related FM11RF08 and FM11RF32 chips), which had shipped in hotel and transit cards in a number of countries. Genuine NXP MIFARE Classic and the DESFire family are not affected by that specific backdoor.
For a buyer the lesson is not to abandon MIFARE but to specify the exact chip on the purchase order — for example "NXP MIFARE Classic EV1 1K, MF1S50, 7-byte UID" rather than "MIFARE-compatible 1K" — and to test a sample in the actual readers and locks before a bulk order. A part that authenticates in a bench reader can still be rejected by an access system that fingerprints its cards, and a UID-writable clone must be treated as a cloning-class threat by any system that whitelists cards by UID. Tell us the chip your system was built for and we supply that chip; where a specification names a MIFARE-compatible alternative deliberately, we confirm which silicon we can source in the quotation.
MIFARE is a family of chips, not one product, and "MIFARE" on a specification does not tell a reader which member is meant. The table sets Classic against its relatives so you can match the card to what the system actually needs; a chip named in your integrator's specification always wins over this summary.
| Family member | Memory | Security / interface | Typical role |
| MIFARE Ultralight / EV1 / C | 48–192 bytes | No authentication, or 3DES (Ultralight C); ISO 14443-3A | Single-use transit tickets, event and paper wristbands (specified per project) |
| MIFARE Classic 1K / 4K (EV1) | 1 KB / 4 KB | Crypto-1, 48-bit (broken); ISO 14443-3A | Hotel keys, legacy access, membership — this page and the 4K card |
| MIFARE Plus | 2 KB / 4 KB | AES-128, Classic-compatible in SL1; ISO 14443-3A/4 | Phased Classic-to-AES migration in the same readers |
| MIFARE DESFire EV2 / EV3 | 2 / 4 / 8 KB | AES-128, secure messaging, file-level access; ISO 14443-4 | Multi-application access, transit and payment; see the DESFire EV2 card |
| SmartMX / Java Card | Configurable | Certified secure element running Java Card applets; ISO 14443-4 | Government ID, banking and high-assurance multi-application programmes |
We manufacture MIFARE Classic cards, fobs, wristbands and stickers with genuine NXP chips, printed and personalised to your specification, and can provide a UID list for the order. We do not supply access-control readers, locks or software, and we do not duplicate cards from systems the buyer does not administer. If your system is due for a security upgrade, compare the MIFARE Plus card and MIFARE DESFire cards, or see all our RFID cards.
Memory only: 1K has 1024 bytes in 16 sectors, 4K has 4096 bytes in 40 sectors. The air interface, keys and security are identical, so both work in the same readers. 1K covers access control, hotel keys and membership; 4K is used when several applications or transaction records share one card.
Its Crypto-1 cipher was broken in 2008 and keys can be recovered from a card, so Classic should not be chosen for new systems that store value or must resist cloning. It remains adequate where the card is only an identifier checked by the back-end, and it is the only option when the installed readers and locks are Classic-only. MIFARE Plus offers an AES upgrade path in the same readers.
Older systems that enrol cards by UID were built for the 4-byte non-unique ID; current readers usually accept both. Ask your integrator or lock vendor, or send us a working card and we will match it. Testing a sample before a large order is the safest approach.
On Android, Classic support depends on the phone hardware and app; protected sector access also requires the correct keys. Do not rely on iPhone Core NFC for Classic sector reading or writing. For phone-facing NDEF data, consider an NFC Forum tag such as NTAG and verify the intended phones and app.
The standard card is ISO/IEC 7810 ID-1, 85.6 × 54 mm and about 0.76 to 0.84 mm thick, the same as a bank card. Thin cards of 0.3 to 0.5 mm, key fobs, wristbands and stickers use the same chip in other shapes.
Yes. Because the cipher is broken, the sector data of a genuine card can be read and written to a third-party card with a changeable UID. Systems that need protection against this should authenticate with diversified keys and plan a migration to MIFARE Plus or DESFire. We supply only genuine NXP chips with locked UIDs and do not duplicate cards from systems the buyer does not administer.
By default they ship blank with the factory transport keys (all FF), which is how most integrators want them. On request we load your sector keys and data, print the UID or an assigned number on the card, and deliver a matching CSV list.
MIFARE is NXP's family of 13.56 MHz contactless smart-card chips built on the ISO/IEC 14443 Type A air interface. It is not a single product: the family runs from the memory-only Ultralight, through the classic sector-and-key MIFARE Classic, to the AES-secured MIFARE Plus and the multi-application DESFire. Because the name covers all of these, a specification should always name the exact member, such as MIFARE Classic EV1 1K, rather than just MIFARE.
Crypto-1 is the proprietary 48-bit stream cipher that authenticates each sector of a MIFARE Classic card. It was reverse-engineered from the silicon (Nohl and Plötz, presented in 2007) and fully broken with practical key-recovery attacks published by Radboud University researchers in 2008. Later nested, darkside and hardnested attacks made key recovery a matter of seconds to minutes with free tools on inexpensive hardware. The cipher cannot be patched, which is why Classic is treated as a convenience credential rather than a security one.
No. Chips such as the Fudan FM11RF08 implement the ISO 14443-3A layer and Crypto-1 command set closely enough to work in many Classic readers, and often present the same ATQA and SAK as a genuine chip, but they differ in UID writability, edge-case behaviour and anti-counterfeit features. A backdoor key in Fudan FM11RF08-family chips was publicly disclosed in August 2024. Specify the exact chip on your order and test a sample in the real readers; tell us which silicon your system requires and we supply it.
A 1K chip is 1024 bytes in total: 16 sectors of 4 blocks of 16 bytes. After the sector trailers (one per sector) and the read-only manufacturer block in sector 0, roughly 752 bytes are usable for data. A 4K chip holds 4096 bytes across 40 sectors, of which about 3440 bytes are usable. A door credential needs only a few bytes, so 1K is normal for access control and 4K is chosen when several applications share one card.
Send the product, quantity and application so we can confirm the options and pricing for your project.
