A smart card is a physical card that has an embedded integrated chip that acts as a security token. Smart cards are typically the same size as a driver's license or credit card and can be made out of metal or plastic. They connect to a reader either by direct physical contact -- also known as chip and dip -- or through a short-range wireless connectivity standard such as radio-frequency identification (RFID) or near-field communication.

The chip on a smart card can be either a microcontroller or an embedded memory chip. Smart cards are designed to be tamper-resistant and use encryption to provide protection for in-memory information. Cards with microcontroller chips can perform on-card processing functions and manipulate information in the chip's memory.

智能卡用于各种各样的应用程序but are most commonly used as credit cards and other payment cards. The payment card industry's support of smart cards for the Europay, Mastercard and Visa (EMV) card standard has driven the distribution of smart cards. Smart cards capable of short-range wireless connectivity can be used for contactless payment systems. They can also be used as tokens for multifactor authentication (MFA).

How smart cards work

Smart card microprocessors or memory chips exchange data with card readers and other systems over a serial interface. The smart card itself is powered by an external source, usually the smart card reader.

Smart cards communicate with readers via direct physical contact or using RFID or another short-range wireless connectivity standard. The chip or processor on the card contains data that the card reader accesses. The processor on the card contains a basic operating system (OS) that lets the card hold, transmit and protect the data.

The card reader passes data from the smart card to its intended destination, usually a payment or authentication system, over a network connection.

Advantages of smart cards

Smart cards offer several advantages, such as these: Stronger security. Smart cards provide a higher level of security than magnetic stripe cards because they contain microprocessors capable of processing data directly without remote connections. Even memory-only smart cards can be more secure because they can store more authentication and account data than traditional mag stripe cards. Smart cards are generally safe against electronic interference and magnetic fields, unlike magnetic stripe cards.

Information persistence. Once information is stored on a smart card, it can't be easily deleted, erased or altered. That is why smart cards are good for storing valuable data that should not be reproduced. However, applications and data on a card can be updated through secure channels, so issuers do not have to issue new cards when an update is needed.

Multiple uses. Multiservice smart card systems let users access more than one service with one smart card.

Disadvantages of smart cards

While smart cards have many advantages, there also drawbacks, including the following:

Cost. The cards and the smart card readers can be expensive.

Compatibility. Not all smart card readers are compatible with all types of smart cards. Some readers use nonstandard protocols for data storage and card interface, and some smart cards and readers use proprietary software that is incompatible with other readers.

Security vulnerabilities. Smart cards are secure for many applications, but they are still vulnerable to certain types of attack. For example, attacks that can recover information from the chip can target smart card technology. Differential power analysis (DPA) can be used to deduce the on-chip private key used by public key algorithms, such as the Rivest-Shamir-Adleman (RSA) algorithm. Some implementations of symmetric ciphers are vulnerable to timing attacks or DPA. Smart cards may also be physically disassembled in order to gain access to the onboard microchip.