With the transition to paperless environment the e-business and e-government processes demand to prove the existence of data at a specific point of time and to demonstrate the integrity of the data since that time during long term periods is becoming of utmost importance. Through the course of time the true value of electronic content may simply evaporate due to technological progress and incompetence to prove the authenticity of data stored. This paper presents an approach and a solution to the problem of long-term preservation of electronic data for dematerialized business processes. The basic system design and the architecture of a long-term electronic archive service is introducing a protocol and an evidence record syntax that is being standardized within the IETF Long Term Archive and Notarization Service Working Group. The proposed system environment is based PKI-enabled services for creation of long term integrity proofs. Furthermore, the solution contains additional class of services that meet the requirements for long term validity of digitally signed and legally binding documentation.