Kerbs On Security goes over the two main methods of credit card security using an embedded chip in the card itself (which are not yet widely available in the USA, although prevalent in Europe and other parts of the world).
The United States is the last of the G20 nations to move to more secure chip-based cards. Other countries that have made this shift have done so by government fiat mandating the use of chip-and-PIN. Requiring a PIN at each transaction addresses both the card counterfeiting problem, as well as the use of lost or stolen cards.
Here in the States, however, the movement to chip-based cards has evolved overwhelmingly toward the chip-and-signature approach. Naturally, if your chip-and-signature card is lost or stolen and used fraudulently, there is little likelihood that a $9-per-hour checkout clerk is going to bat an eyelash at a thief who signs your name when using your stolen card to buy stuff at retailers. Nor will a signature card stop thieves from using a counterfeit card at automated payment terminals (think gas pumps).KrebsOnSecurity