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.