A method for releasing a transaction by a computer system , the method comprising - transmitting transaction details from the computer system to a chip card , the transaction details including specific information about the transaction, - receiving the transaction details by the chip card , - displaying the transaction details and a transaction number on a display of the chip card , the transaction number being specific to the transaction, - receiving the transaction number by the computer system on account of a user input of the transaction number, - validating the transaction number by the computer system , and - releasing the transaction if the received transaction number has been validated as valid, wherein the transaction details are received by the chip card via an interface for near-field communication, wherein the transmission of the transaction details from the computer system to the chip card includes a transmission of the transaction details to a mobile telecommunications device and from the mobile telecommunications device to the interface of the chip card , wherein the transmission of the transaction details from the computer system to the mobile telecommunications device includes: - a visual or acoustic provision, by the computer system , of a code detectable visually or acoustically by the mobile telecommunications device , - receiving of the transaction details by the mobile telecommunications device on account of a visual or acoustic detection of the code by the mobile telecommunications device . - transmitting transaction details from the computer system to a chip card , the transaction details including specific information about the transaction, - receiving the transaction details by the chip card , - displaying the transaction details and a transaction number on a display of the chip card , the transaction number being specific to the transaction, - receiving the transaction number by the computer system on account of a user input of the transaction number, - validating the transaction number by the computer system , and - releasing the transaction if the received transaction number has been validated as valid, wherein the transaction details are received by the chip card via an interface for near-field communication, wherein the transmission of the transaction details from the computer system to the chip card includes a transmission of the transaction details to a mobile telecommunications device and from the mobile telecommunications device to the interface of the chip card , wherein the transmission of the transaction details from the computer system to the mobile telecommunications device includes: - a visual or acoustic provision, by the computer system , of a code detectable visually or acoustically by the mobile telecommunications device , - receiving of the transaction details by the mobile telecommunications device on account of a visual or acoustic detection of the code by the mobile telecommunications device . - a visual or acoustic provision, by the computer system , of a code detectable visually or acoustically by the mobile telecommunications device , - receiving of the transaction details by the mobile telecommunications device on account of a visual or acoustic detection of the code by the mobile telecommunications device . <EOS>