Abstract: A PTC heating element for an electric heater having a PTC element, an electrode formed on a surface of the PTC element for electrically contacting the PTC element, at least one additional contact for electrically connecting the electrode of the PTC element, and a carrier layer. The carrier layer is electrically insulating, the thickness of the PTC element is ?500 ?m, and the installation height of the PTC heating element is between 500 ?m and 2500 ?m. Also disclosed is an electric heater and use of the PTC heating element in a motor vehicle.

Abstract: A method creates and distributes cryptographic keys for securing communication at two terminals. Signals for creating correlated values in the two terminals are distributed via a first communication channel burdened with error, and the correlated values are present as keys. A checksum is formed on the basis of the first key present in the first terminal and the checksum is transferred to the second terminal via a second communication channel. A second checksum is formed on the basis of the second key present, and information derived from the two checksums is transferred via the second communication channel to a server. Based on the information derived from the checksums, the server determines a correction value, which, when applied to one or both keys, brings the keys into correspondence. The correction value is transferred to one or both terminals via the second communication channel and is applied to one or both keys.

Abstract: A method for checking the availability and integrity of a data object stored on a plurality of servers and having a number N of data words. For the distributed storage on the servers, the data object is fragmented. Each fragment is transmitted to and stored on one server. To check the availability and integrity of the fragments stored on the servers, the same random number is sent from an auditor unit to the servers. A checksum is created by the servers, in each case modified by application of the random number to the data of the respective fragment, and the checksum is transmitted to the auditor unit. The auditor unit uses the consistency check to determine whether the individual checksums sent by the servers are consistent and, if this is the case, establishes the availability and integrity of the data.

Abstract: A method creates and distributes cryptographic keys for securing communication at two terminals. Signals for creating correlated values in the two terminals are distributed via a first communication channel burdened with error, and the correlated values are present as keys. A checksum is formed on the basis of the first key present in the first terminal and the checksum is transferred to the second terminal via a second communication channel. A second checksum is formed on the basis of the second key present, and information derived from the two checksums is transferred via the second communication channel to a server. Based on the information derived from the checksums, the server determines a correction value, which, when applied to one or both keys, brings the keys into correspondence. The correction value is transferred to one or both terminals via the second communication channel and is applied to one or both keys.

Abstract: A method for a re-issuance of an attribute-based credential of an issuer of the attribute-based credential for a user may be provided. The user is holding backup values derived from a first credential previously obtained from the issuer, wherein the first credential is built using at least a first value of at least one authentication pair. The method comprises receiving by the issuer from the user a set of values derived from the backup values comprising a second value of the at least one authentication pair, validating by the issuer that the second value is a valid authentication answer with respect to the first value and whether the set of values was derived from a valid first credential, and providing by the issuer a second credential to the user based on the first set of values.

Abstract: A method for checking the availability and integrity of a data object stored on a plurality of servers and having a number N of data words. For the distributed storage on the servers, the data object is fragmented. Each fragment is transmitted to and stored on one server. To check the availability and integrity of the fragments stored on the servers, the same random number is sent from an auditor unit to the servers. A checksum is created by the servers, in each case modified by application of the random number to the data of the respective fragment, and the checksum is transmitted to the auditor unit. The auditor unit uses the consistency check to determine whether the individual checksums sent by the servers are consistent and, if this is the case, establishes the availability and integrity of the data.

Abstract: A user computer generates a secret cryptographic key through communication with a server. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. In response to input of an input password, the user computer encodes the secret user value and the input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first value and check value to check whether the input password equals the user password. If so, the server encodes the first value and secret server value to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

Abstract: A user computer generates a secret cryptographic key through communication with a server. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. In response to input of an input password, the user computer encodes the secret user value and the input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first value and check value to check whether the input password equals the user password. If so, the server encodes the first value and secret server value to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

Abstract: Methods and apparatus are provided for generating a secret cryptographic key of a user computer connectable to a server via a network. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. The user computer encodes the secret user value and an input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first and the check values to check whether the input password equals the user password. If so, the server encodes the first and the secret server values to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

Abstract: A method for a re-issuance of an attribute-based credential of an issuer of the attribute-based credential for a user may be provided. The user is holding backup values derived from a first credential previously obtained from the issuer, wherein the first credential is built using at least a first value of at least one authentication pair. The method comprises receiving by the issuer from the user a set of values derived from the backup values comprising a second value of the at least one authentication pair, validating by the issuer that the second value is a valid authentication answer with respect to the first value and whether the set of values was derived from a valid first credential, and providing by the issuer a second credential to the user based on the first set of values.

Abstract: A method for a re-issuance of an attribute-based credential of an issuer of the attribute-based credential for a user may be provided. The user is holding backup values derived from a first credential previously obtained from the issuer, wherein the first credential is built using at least a first value of at least one authentication pair. The method comprises receiving by the issuer from the user a set of values derived from the backup values comprising a second value of the at least one authentication pair, validating by the issuer that the second value is a valid authentication answer with respect to the first value and whether the set of values was derived from a valid first credential, and providing by the issuer a second credential to the user based on the first set of values.

Abstract: Methods and apparatus are provided for generating a secret cryptographic key of a user computer connectable to a server via a network. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. The user computer encodes the secret user value and an input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first and the check values to check whether the input password equals the user password. If so, the server encodes the first and the secret server values to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

Abstract: A method for a re-issuance of an attribute-based credential of an issuer of the attribute-based credential for a user may be provided. The user is holding backup values derived from a first credential previously obtained from the issuer, wherein the first credential is built using at least a first value of at least one authentication pair. The method comprises receiving by the issuer from the user a set of values derived from the backup values comprising a second value of the at least one authentication pair, validating by the issuer that the second value is a valid authentication answer with respect to the first value and whether the set of values was derived from a valid first credential, and providing by the issuer a second credential to the user based on the first set of values.

Abstract: A fabric web delivery apparatus is provided with a pivotable and vertically adjustable fabric delivery arm having a driven delivery roller at its outward end and also with an independently reciprocable cuttle arm enabling selective positioning of the delivery arm for disposition of the delivery roller alternatively for feeding a traveling fabric web to the cuttle arm for folding the web in pleats, or for peripheral driving contact with a fabric winding roll of a surface-driven fabric winder, or for guiding a traveling fabric web to a fabric winding roll of an axis-driven fabric winder, or for operation as a support roller for a fabric winding roll of a rising-type fabric winder.