MIFARE Classic 4K card is a type of contactless smart card based on the ISO/IEC 14443 Type A standard. It is widely used in applications such as public transport, access control, and electronic payment systems. The “4K” in its name indicates that it has 4 kilobytes (4096 bytes) of memory.
Key Features
- Memory Capacity:
- 4 KB (4096 bytes), divided into 40 sectors of data.
- Each sector is further subdivided into 16 blocks, and each block holds 16 bytes of data.
- Data Authentication:
- Uses cryptographic keys (A and B) for access control to sectors.
- Supports proprietary encryption algorithms (CRYPTO1) for authentication.
- Communication:
- Operates on a 13.56 MHz frequency (RFID standard).
- Data transfer rate: 106 kbit/s.
- Application Flexibility:
- Multiple sectors allow partitioning for different purposes (e.g., transport ticketing and building access).
- Durability:
- Designed for at least 100,000 write cycles and over 10 years of data retention.
Common Applications
- Public Transit: Fare cards in buses, trains, and subways.
- Access Control: Secure entry for offices, hotels, and other facilities.
- Loyalty Cards: Retail loyalty systems and prepaid cards.
- Parking Systems: Automated payment and identification.
Security Considerations
While the MIFARE Classic 4K is popular, it is considered outdated in terms of security. The proprietary CRYPTO1 encryption has been compromised, making it vulnerable to attacks like:
- Replay Attacks: Mifare 4k Classic Card is intercepting and reusing legitimate communication.
- Key Extraction: Breaking the cryptographic keys.
For new systems, NXP (the manufacturer) recommends migrating to more secure alternatives like MIFARE Plus or MIFARE DESFire, which offer advanced encryption methods like AES or Triple DES.
MIFARE Cards
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