Understanding Cards & Readers - 125 kHz vs 13.56 MHz

Understanding Cards & Readers  
125kHz vs 13.56MHz

Standard Prox - 125 kHz (Low Frequency) Cards

These are simple proximity cards with no encryption.
Standard Prox cards are the most basic type of access card. They are widely used because they are affordable and easy to set up. However, they offer the lowest level of security because the information on the card is not encrypted, making it easier for someone to copy or clone the card.

13.56 MHz (High Frequency) Smart Cards

13.56 MHz are contactless smart cards that can store more data and support encryption. They offer a higher level of security than Standard Prox cards. Unlike basic proximity cards, they can use encryption to protect the data stored on the card, making them much harder to copy or clone.

13.56 MHz smart cards are available in different versions, each offering different levels of security. 

The MIFARE family includes options such as MIFARE Classic, MIFARE Plus, and MIFARE DESFire, with security improving across the different versions.

Although MIFARE Classic remains widely deployed globally, it is no longer considered suitable for high-security applications due to known vulnerabilities. Newer technologies, such as MIFARE DESFire, have been developed to provide enhanced security and stronger authentication.

 MIFARE DESFire uses strong encryption and advanced security features to protect card data, making it much more difficult to copy or clone. Unlike older card technologies, DESFire uses AES encryption, secure authentication, and encrypted communication between the card and reader. This means the card and reader verify each other before allowing access, helping prevent card cloning and unauthorised access to the card data.

125kHz (Low Frequency / LF) – SP Readers

125kHz readers, often referred to as Standard Prox readers, read the unique serial number stored on the card and use this as the badge number for access control. These readers are commonly used with standard prox cards and provide a simple, reliable method of identification, but they do not support encryption or advanced security features.

Proximity readers work by constantly emitting a short range radio frequency (RF) field. When a proximity card comes within range of this field, an integrated chip within the card is powered up and the chip transmits a card number back to the reader.

When a 125kHz card comes within range of a reader, the card immediately begins to transmit its card number. The data transmitted by the card is not encrypted and is always the same. Data transfer is only one way.

SF/DF Readers - 13.56 MHz

These readers were created to address the security issues with 125kHz technology by enabling two way communication between the card and reader. This saw the introduction of card encryption and the ability to store data on the card.

Most MIFARE technologies store the card number in one of the storage areas on the card, known as sectors. When the card approaches the RF field of the reader, the card and reader begin a secure communication session using shared encryption keys. Once this is established, the card number is transmitted and the communication session is closed off. This process happens very quickly, however it does take slightly longer than a 125kHz based system and means that generally, a MIFARE card cannot be simply swiped or waved at a card reader, but must be presented. Also, the two way process requires more energy than 125kHz, meaning a slightly reduced read range of around 7cm (2.7in).

Along with the added security, the additional storage space on the card can be used for many applications, such as offline locking systems or the storage of credit for pay as you go systems.

Every Mifare card has its own unique identifier hard-stamped from the factory.

Operating in the high-frequency band (often associated with NFC), this is the standard for modern contactless operations like public transit, payment terminals, and advanced building security