MIFARE 13.56 MHz Compatible card available

MIFARE Classic 4K Compatible Cards & Fobs

MIFARE Classic 4K expands on the 1K format with 4,096 bytes across 40 sectors for multi-application campus and transit use, but shares the same broken CRYPTO1 cipher that makes all MIFARE Classic cards cloneable with off-the-shelf tools.

Quote MIFARE Classic 4K cards View specs

MIFARE Classic 4K operates at 13.56 MHz per ISO/IEC 14443 Type A, offering 4 KB of EEPROM split into 32 small sectors (4 blocks each) and 8 large sectors (16 blocks each), enabling multiple simultaneous applications on a single card. Like the 1K variant, it relies on the CRYPTO1 stream cipher, which has been publicly compromised since 2008, meaning cards can be fully cloned onto magic-UID writable blanks — making it appropriate only for legacy continuity rather than new security-sensitive deployments.

MIFARE Classic 4K specifications

Brand / OEM
NXP Semiconductors
Technology
Contactless smart card (ISO/IEC 14443 Type A)
Frequency
13.56 MHz
Chip
NXP MF1S70YYX (EV1 variant: MF1S70YYX_V1); 4,096-byte EEPROM organized in 32 sectors × 4 blocks plus 8 sectors × 16 blocks; 4-byte or 7-byte UID; CRYPTO1 stream cipher
Bit formats
26-bit Wiegand (H10301) via reader-side UID extraction, 37-bit Wiegand, Custom multi-application encoding across sector data blocks
OEM part numbers
MF1S7023YDU/D, MF1S7035YDU/D, MF1S70YYX_V1, MF1ICS70

Our compatible MIFARE Classic 4K credentials

American Key Cards manufactures non-OEM credentials engineered to work with your existing MIFARE readers — no hardware changes, encoded to your facility code and card-number range.

AKC MIFARE Classic 4K Compatible CardProximity / ISO card
AKC MIFARE Classic 4K Compatible Key FobKey fob / tag

Can MIFARE Classic 4K cards be copied?

MIFARE Classic 4K is an open format, so a compatible card can be produced from your facility code and card number. We don't copy individual cards on request — we manufacture new, correctly-encoded credentials for systems you own or manage.

CRYPTO1 encryption is cryptographically broken — same vulnerability as MIFARE Classic 1K. All 40 sectors can be compromised and the card duplicated with Proxmark3 and magic-UID writable blanks. The larger memory offers no additional security benefit over 1K. Not recommended for new high-security deployments; consider MIFARE DESFire EV3 for multi-application use cases requiring genuine cryptographic protection.

Where MIFARE Classic 4K is used

  • University multi-application campus cards (access + dining + printing + library)
  • Large enterprise campuses requiring multiple access zones in separate sectors
  • Transit systems with extended fare and loyalty data
  • Healthcare facility multi-function ID cards
  • Corporate campuses combining logical and physical access data

Compatible readers

HID multiCLASS SE (RP10, RP15, RP40) readersAllegion aptiQ multi-technology readersLenelS2 BlueDiamond multi-tech readersDormakaba MIFARE-capable readersAny ISO 14443A reader supporting MIFARE Classic 4K

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MIFARE Classic 1K

MIFARE Classic 1K is the world's most-deployed contactless smart card format, running at 13.56 MHz with 1 KB of CRYPTO1-protected memory across 16 sectors — widely used in legacy access control and hotel lock systems but known to be cloneable.

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MIFARE Plus

MIFARE Plus is NXP's drop-in AES-128 upgrade path for MIFARE Classic infrastructure, offering backward-compatible SL1 mode (readable by Classic readers) and fully secure SL3 mode (AES-128, not cloneable) on a single card platform.

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HID iCLASS SE

HID iCLASS SE is the second-generation 13.56 MHz smart card platform, introducing Secure Identity Objects (SIOs) and AES encryption to make credential cloning technically infeasible.

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MIFARE Classic 4K — FAQ

What is the difference between MIFARE Classic 1K and 4K?

The 4K variant provides 4,096 bytes across 40 sectors (versus 16 sectors on 1K), allowing more simultaneous applications — such as access control, transit, cafeteria balance, and library borrowing — stored in separate sectors on a single card. Both use the same broken CRYPTO1 cipher and carry the same cloneability risk.

Can MIFARE Classic 4K cards be cloned?

Yes — CRYPTO1 is broken on 4K exactly as it is on 1K. All sector keys can be recovered and the full 4K image can be copied to a magic blank card. The larger memory does not provide any additional security against cloning.

Are MIFARE Classic 4K cards backward compatible with 1K readers?

MIFARE Classic 4K cards use the same ISO 14443A protocol and CRYPTO1 cipher as 1K, so any reader capable of handling MIFARE Classic will read a 4K card's UID and Sector 0 data. However, applications that specifically address sectors 17–39 (the large 16-block sectors) require 4K-aware firmware.