Abstract: Methods and a system involve secure communication between an RFID tag and a reader via the over-the-air interface, and to corresponding RFID tags and corresponding readers. A modification of the Rabin method is employed wherein within the framework of the encryption of a plaintext M into which an identification element of the RFID tag or of an object furnished therewith is incorporated, there is computed by the RFID tag, the Montgomery residue (Montgomery reduction) of the square of the plaintext M modulo n with respect to a Montgomery base R, i.e. C*=M2R?1 mod n, and the resultant ciphertext C* is employed for authenticating the RFID tag. The modulus n=p·q is the public key of the reader, the prime numbers p, q are the private key of the reader, and the Montgomery base R is an integer that is larger than the modulus n.

Abstract: A method for monitoring a system includes reading devices and a plurality of portable communication units, wherein during operation of the system, for a communication unit there are carried out a plurality of data transactions between at least one reading device and the communication unit via a corresponding communication interface. Within the framework of a data transaction a first data set is transferred from a reading device to the communication unit and stored. A second data set stored in the communication unit is transferred to the reading device. Chaining occurs with first and second data sets of the respective data transactions are formed so that in two consecutive data pairs the first data set of the one data pair corresponds to the second data set of the other data pair, and a criterion is checked for being fulfilled.

Abstract: Methods and a system involve secure communication between an RFID tag and a reader via the over-the-air interface, and to corresponding RFID tags and corresponding readers. A modification of the Rabin method is employed wherein within the framework of the encryption of a plaintext M into which an identification element of the RFID tag or of an object furnished therewith is incorporated, there is computed by the RFID tag, the Montgomery residue (Montgomery reduction) of the square of the plaintext M modulo n with respect to a Montgomery base R, i.e. C*=M2R?1 mod n, and the resultant ciphertext C* is employed for authenticating the RFID tag. The modulus n=p·q is the public key of the reader, the prime numbers p, q are the private key of the reader, and the Montgomery base R is an integer that is larger than the modulus n.

Abstract: Methods and a system involve secure communication between an RFID tag and a reader via the over-the-air interface, and to corresponding RFID tags and corresponding readers. A modification of the Rabin method is employed wherein within the framework of the encryption of a plaintext M into which an identification element of the RFID tag or of an object furnished therewith is incorporated, there is computed by the RFID tag, the Montgomery residue (Montgomery reduction) of the square of the plaintext M modulo n with respect to a Montgomery base R, i.e. C*=M2R?1 mod n, and the resultant ciphertext C* is employed for authenticating the RFID tag. The modulus n=p·q is the public key of the reader, the prime numbers p, q are the private key of the reader, and the Montgomery base R is an integer that is larger than the modulus n.

Abstract: A method for monitoring a system includes reading devices and a plurality of portable communication units, wherein during operation of the system, for a communication unit there are carried out a plurality of data transactions between at least one reading device and the communication unit via a corresponding communication interface. Within the framework of a data transaction a first data set is transferred from a reading device to the communication unit and stored. A second data set stored in the communication unit is transferred to the reading device. Chaining occurs with first and second data sets of the respective data transactions are formed so that in two consecutive data pairs the first data set of the one data pair corresponds to the second data set of the other data pair, and a criterion is checked for being fulfilled.

Abstract: Methods and a system involve secure communication between an RFID tag and a reader via the over-the-air interface, and to corresponding RFID tags and corresponding readers. A modification of the Rabin method is employed wherein within the framework of the encryption of a plaintext M into which an identification element of the RFID tag or of an object furnished therewith is incorporated, there is computed by the RFID tag, the Montgomery residue (Montgomery reduction) of the square of the plaintext M modulo n with respect to a Montgomery base R, i.e. C*=M2R?1 mod n, and the resultant ciphertext C* is employed for authenticating the RFID tag. The modulus n=p·q is the public key of the reader, the prime numbers p, q are the private key of the reader, and the Montgomery base R is an integer that is larger than the modulus n.

Abstract: In a method for writing (S9, S11) of operating data (6) through a writing system (1, 2) comprising a central station (1) and at least one distribution station (2) to a portable data carrier (3) connected with the at least one distribution station (2) within the framework of a production of the data carrier (3) there is generated (S4, S5) an individual addressing for the data carrier (3) connected with the at least one distribution station (2), via which addressing the data carrier (3) is uniquely addressable system-wide upon the writing (S9, S11) of the operating data (6). In doing so, at least a part of the system-wide unique individual addressing can be generated (S4, S5) by the data carrier (3) itself or by the distribution station (2) with which the data carrier (3) is connected.

Abstract: The invention relates to a method for carrying out an application with the help of a portable data carrier (1). With the method according to the invention via a first data channel (5) of the portable data carrier (1) a data connection with a first external device (2) is formed. Involving the first external device (2), a first part of the application is executed. Via a second data channel (6) of the portable data carrier (1) a data connection with the first or a second external device (3) is formed. From the portable data carrier (1) via the second interface (6) there are transferred identification data, which were provided on the execution of the first part of the application, to the external device (3). A second part of the application is not executed until after a release by a user.

Abstract: In a method for writing (S9, S11) of operating data (6) through a writing system (1, 2) comprising a central station (1) and at least one distribution station (2) to a portable data carrier (3) connected with the at least one distribution station (2) within the framework of a production of the data carrier (3) there is generated (S4, S5) an individual addressing for the data carrier (3) connected with the at least one distribution station (2), via which addressing the data carrier (3) is uniquely addressable system-wide upon the writing (S9, S11) of the operating data (6). In doing so, at least a part of the system-wide unique individual addressing can be generated (S4, S5) by the data carrier (3) itself or by the distribution station (2) with which the data carrier (3) is connected.

Abstract: The invention relates to a method for carrying out an application with the help of a portable data carrier (1). With the method according to the invention via a first data channel (5) of the portable data carrier (1) a data connection with a first external device (2) is formed. Involving the first external device (2), a first part of the application is executed. Via a second data channel (6) of the portable data carrier (1) a data connection with the first or a second external device (3) is formed. From the portable data carrier (1) via the second interface (6) there are transferred identification data, which were provided on the execution of the first part of the application, to the external device (3). A second part of the application is not executed until after a release by a user.

Abstract: A system is proposed for performing transactions with terminals which fundamentally allow a plurality of different transactions to be performed. The terminals (10, 11) are connected for this purpose via a terminal network (30) with at least one node computer (40, 41) via which they can be set up for performing a transaction. The suitability for performing a further, hitherto unprepared transaction can be provided later anytime without any special setup measures. A terminal (10, 11) requests for this purpose data providing the functionality required for performing the further transaction from a node computer (40, 41) following a trigger signal designating the further transaction. The transaction is then performed in interaction between a terminal (10, 11) and a node computer (40, 41).