A system and method for pseudonymizing digital data records sent from a source system to a destination system, using an identity protector client system and an identity protector master system, includes the steps of receiving, at the identity protector client, person-specific data from a source system provided with a source identifier. The digital data records are pre-pseudonymized by the identity protector client, and the processed digital data records are marked with a source identifier which references the source file in the source system. The pre-pseudonymized digital data records are transmitted to the identity protector master. For every data record, a pseudonym is created by the identity protector master from the pre-pseudonym, the source identifier, and at least one other value generated from an erratic value and a time value. The pseudonym is transmitted to the destination system.