The most common access card worldwide is a proximity card. Proximity cards contain a computer chip that receives radio frequency energy from the reader, and its processor transmits the card number to the reader. These cards do have limitations, however. They transmit at a low, limited frequency range and lack additional security features such as two-way communication, memory space and processing power for other applications. The data is also transmitted unencrypted, leaving it more susceptible to attacks.
Smart cards are some of the newer technologies in the access control industry. These can be contact or contactless smart cards. A contact smart card contains an embedded microprocessor chip. These are most often used for logical access – secure computer log-on, data encryption or document signing if PKI is involved. A contactless smart card is essentially a mini-computer. It holds a microprocessor, memory, software programs, security and more. It gets its power from electromagnetic radio waves from the reader, similar to proximity cards. Custom card number formats can be used to lengthen the standard 26-bit format. This adds a layer of security, but make sure that your reader can manage custom or nonstandard formats.