Integrity, authenticity, non-repudiation, and proof of existence for long-term archiving: A survey.

The world increasingly depends on archives to store digital documents, such as land registers and medical records, for long periods of time. For stored documents to remain trustworthy, archives must provide proofs that a document existed on a certain date and has not been changed since. In addition, in many cases, the origin of the document must be verifiable and the originator must not be able to repudiate that she is the originator. In this paper, we survey the solutions that provide the above protection goals in the long term. We analyze and compare the solutions with respect to their functionalities (which protection goals do they achieve?), the trust assumptions they require, and their performance. From this analysis and comparison, we deduce deficiencies of the current solutions and important research problems that must be solved in order to come up with protection solutions that are even more satisfactory.