Abstract: The invention relates to an innovative device which is used to secure payments or transactions made with a smart card and to validate the identity of the smart card holder using a client/server biometric control operation, regardless of whether said payments or transactions are made directly at a point of sale or from a PC (personal computer or shared open-access computer) which is connected to the Internet or using a mobile telephone, a portable computer (also known as a laptop), a PDA (Personal Device Assistant) or any other mobile or fixed means that can connect to any telecommunication network and carry out a transaction involving the use of biometrics at the transaction generation point. The invention also relates to smart-card-holding employees of financial institutions who perform professional inter-bank transfers.