An increasingly large number of digital documents, need to be preserved by organizations. Business documents such as various contracts may be of great business value, may only exit in digital form and may need to be preserved for longer periods of times that may span over decades or even centuries. The preservation process should take care of both the integrity and authenticity of digital documents, providing proofs of document authenticity. Solutions providing these security properties do exist in the market. In this paper we look into long term archiving best practices and capture them on a more abstract, generic level, providing a set of core long term archiving security patterns.