Like anonymization, pseudonymization is also defined in the German Federal Data Protection Act(BDSG). According to this, pseudonymization is "the replacement of the name and other identifying characteristics by a marker for the purpose of excluding or significantly complicating the identification of the person concerned."
Pseudonymization is also about disguising personal identity characteristics so that unauthorized persons cannot draw any conclusions about the person. For this purpose, pseudonyms are used, i.e., imaginary names or nicknames, or, as in the case of anonymization, the personal name is removed from data records and two data records with the same identification number are used. One data set contains no personal data, the other contains only the personal data. Both data sets are kept separately and are directly related to each other via the identification number. Only when they are merged are conclusions about the person possible.
Pseudonymization is used, among other things, in chats and blogs to conceal one's own identity.