Abstract: An OT or Oblivious Transfer protocol is used to output pseudonym tokens from a list of pseudonym tokens to user entities such that it is possible to obtain pseudonymized authentication by a preceding verification of proof of identity of the respective user entities and marking pseudonym tokens as used as soon as the same are used for authentication by means of the OT protocol after the output.

Abstract: In a method of providing a virtual product to third parties, the virtual product being present in an original version in a digital form having a predetermined quality, a reduced version of the virtual product, along with information relating to a distributor of the virtual product, is initially provided. The reduced version's quality is inferior to the quality of the original version, and the information relating to the distributor are associated with this reduced version. On the basis of the information associated with the reduced version, further information may be created. This further information indicates that the reduced version has been passed on to the third party by the content provider. The further information is created if the third party has acquired rights to the virtual product after having obtained the reduced version of same.

Abstract: An OT or Oblivious Transfer protocol is used to output pseudonym tokens from a list of pseudonym tokens to user entities such that it is possible to obtain pseudonymized authentication by a preceding verification of proof of identity of the respective user entities and marking pseudonym tokens as used as soon as the same are used for authentication by means of the OT protocol after the output.

Abstract: In a method of providing a virtual product to third parties, the virtual product being present in an original version in a digital form having a predetermined quality, a reduced version of the virtual product, along with information relating to a distributor of the virtual product, is initially provided. The reduced version's quality is inferior to the quality of the original version, and the information relating to the distributor are associated with this reduced version. On the basis of the information associated with the reduced version, further information may be created. This further information indicates that the reduced version has been passed on to the third party by the content provider. The further information is created if the third party has acquired rights to the virtual product after having obtained the reduced version of same.

Abstract: A device for checking a data set, wherein the data set has a plurality of partial sets and a partial control value per partial set includes a determiner for determining a control value and comparer. The determiner for determining a control value is formed so as to determine a common control value from the partial control values of the partial sets. The comparer is formed so as to compare the common control value to a comparison value provided to the comparer.

Abstract: In a method of providing a virtual product to third parties, the virtual product being present in an original version in a digital form having a predetermined quality, a reduced version of the virtual product, along with information relating to a distributor of the virtual product, is initially provided. The reduced version's quality is inferior to the quality of the original version, and the information relating to the distributor are associated with this reduced version. On the basis of the information associated with the reduced version, further information may be created. This further information indicates that the reduced version has been passed on to the third party by the content provider. The further information is created if the third party has acquired rights to the virtual product after having obtained the reduced version of same.