The healthcare industry is moving from paper-based documentation into the digital era. Electronic health records (EHR) are playing a major role in this development. Electronic health records will not only to be shared among a growing number of healthcare providers but they have also to be archived over long periods of time. The required life cycle depends of national regulations, but typically the preservation time of patient data varies between 20 and 100 years. Availability, integrity, confidentiality and non-repudiation of stored data over these lengthy preservation periods needs to be fully proven, both to preclude loss and also ensure the ability to read and understand content is maintained. This document describes a co-operative trusted notary archive (TNA) which receives granular health data from different EHR-systems, stores data together with associated meta-information for long periods and distributes granular EHR-data objects. TNA communicates with EHR-systems and external users via archive request and distribution messages. TNA can store objects in XML-format and prove the non-repudiation and integrity of stored data with the help of event records, Time-stamps and archive e-signatures.