The smartcard is a chip card with a processor and specialized operating system, that can perform several cryptographic functions on the chip. Usually this is also the assymmetric RSA algorithm but also elliptic curves. Within a PKI X.509 certificates are stored on the smartcard chip togeather with the private key, which will never leave the chip. The functions of the card operating system can use the private key but it will not be exported. Thus the smartcard can be used to sign and decrypt emails and other data. But it can also be used to do two factor authentication at your computers operating system or to authenticate at a full disk encryption. Due to its form factor the smartcard can easily carried in the users purse or printed with names and images it is used as company ID card.
We use the smartcard to do two factor authentication at the operating system and full disk encryption in our customer projects. Smartcards can also be used to do document signing and signing of business processes.