Method for producing a transaction signal

A method for generating a transaction signal using a first device and a second device, wherein at least one of the first device and the second device is configured to be carried by a user, the method comprising:

• the user generating with a first device a first information which depends on an amount,
• transmitting the first information with the first device to a verification device, generating with the verification device in response to the first information a signal which is configured to be converted by the first device into an at least two-dimensional representation adapted to be displayed on a display of the first device, generating with the verification device a first verification information based on the first information,
• transmitting the signal from the verification device to the first device, converting the signal with the first device into the at least two-dimensional representation, and displaying the at least two-dimensional representation on the display of the first device,
• recording the at least two-dimensional representation on the display of the first device with a camera of a second device and producing a recording signal, transmitting the recording signal, or a second information that depends from the recording signal, with the second device to the verification device or to an alternative verification device,
• generating with the verification device or with the alternative verification device from the recording signal or from the second information a second verification information,
• comparing the first verification information with the second verification information, and
• generating the transaction signal when the comparison between the first verification information with the second verification information produces a predetermined result.