A smart card is a device that includes an embedded integrated circuit chip (ICC) that can be either a secure microcontroller or equivalent intelligence with internal memory or a memory chip alone.
The card connects to a reader with direct physical contact or with a remote contactless radio frequency interface. Smart cards can be either contact or contactless smart card. Smart cards can provide personal identification, authentication, data storage, and application processing. Smart cards may provide strong security authentication for single sign-on (SSO) within large organizations. Smart cards have been advertised as suitable for personal identification tasks, because they are engineered to be tamper resistant. The chip usually implements some cryptographic algorithm. There are, however, several methods for recovering some of the algorithm's internal state. Differential power analysis involves measuring the precise time and electric current required for certain encryption or decryption operations. This can deduce the on-chip private key used by public key algorithms such as RSA. Some implementations of symmetric ciphers can be vulnerable to timing or power attacks as well. Smart cards can be physically disassembled by using acid, abrasives, solvents, or some other technique to obtain unrestricted access to the on-board microprocessor. Although such techniques may involve a risk of permanent damage to the chip, they permit much more detailed information (e.g., photomicrographs of encryption hardware) to be extracted.