Apparatus and method for providing pseudonyms

It is proposed an apparatus for providing pseudonyms. The apparatus comprises a calculating unit for calculating a first set of hash values ​​based on a hash function, wherein the calculation unit is configured to calculate each hash value of the first set using a hash function and an input value, each input value to a variation of a common initial value according to a predefined variation scheme is based, with the variation for each input value is different from the variations of the remaining input values, and a providing unit for providing a hash value of the calculated first amount of hash values ​​as a pseudonym on. The proposed device is a top-down calculation of hash values ​​is made. On the basis of an initial secrecy, it is possible to generate a virtually unlimited number of pseudonyms dynamic and efficient. It is further proposed a system comprising a first device and a second device communicating with each other using the pseudonyms generated. Furthermore, a corresponding method for providing pseudonyms is proposed.