Authorization of a transaction

A method for authorizing a transaction by a user using a terminal capable of communicating with a background system, with the steps comprising:

• determining, by the terminal, identification information which identifies the user,
• communicating between the terminal and the background system to authenticate the terminal at the background system and to transmit user identification data from which the identity of the user can be derived to the background system,
• if the authentication of the terminal at the background system has been successful, then the background system accesses secret data stored in a database and assigned to the user, and data from which the secret data can be determined is sent to the terminal,
• playing back, by the terminal, a secret given by the secret data to the user,
• determining, by the terminal, a personal feature of the user, and
• performing the transaction using data pertaining at least to the personal feature of the user.

A terminal which is capable of communicating with a background system and which is equipped for authorizing a transaction by a user, wherein the terminal is adapted for:

• determining identification information which identifies the user,
• sending data to the background system to authenticate the terminal at the background system and to transmit user identification data from which the identity of the user can be derived, to the background system,
• receiving secret data assigned to the user from the background system,
• playing back a secret given by the secret data to the user,
• determining a personal feature of the user, and
• sending data which is related to the personal feature of the user to the background system to signal or document the authorization of the transaction by the user.

A system comprising a background system and at least one terminal capable of communicating with the background system, the system being equipped for authorizing a transaction by a user, wherein the system is adapted for:

• determining, by the terminal, identification information which identifies the user,
• communicating between the terminal and the background system to authenticate the terminal at the background system and to transmit user identification data from which the identity of the user can be derived to the background system,
• if the authentication of the terminal at the background system has been successful, then the background system accesses secret data stored in a database and assigned to the user, and data from which the secret data can be determined is sent to the terminal,
• playing back, by the terminal, a secret given by the secret data to the user,
• determining, by the terminal, a personal feature of the user, and
• performing the transaction using data pertaining at least to the personal feature of the user.

A computer program product having program instructions for at least one processor of a terminal to cause the at least one processor to execute a method for authorizing a transaction by a user, the terminal being capable of communicating with a background system, with steps performed by the terminal comprising:

• determining identification information which identifies the user,
• sending data to the background system to authenticate the terminal at the background system and to transmit user identification data from which the identity of the user can be derived, to the background system,
• receiving secret data assigned to the user from the background system,
• playing back a secret given by the secret data to the user,
• determining a personal feature of the user, and
• sending data which is related to the personal feature of the user to the background system to signal or document the authorization of the transaction by the user.