Proof of Existence is a prototype system that uses blockchain technologies to allow for the permanent and trusted storage of proof that an electronic document or file existed at a certain point.

The prototype system consists of:

  • An API that with calls to record and verify the existence of documents
  • A demo web app, which can:
    • Generate the hash of a file
    • Gather metadata about the file and record its existence
    • Find and retrieve records of existence

The API is the core of the prototype and we’ve integrated it into the EkoSmart (, where it is available for all the users of the platform. The same records in the block chain can also be found without the API, using the Etherscan tool ( or any other tool or software that can analyze the Ethereum blockchain..

Open PoE application


FINANCING: Ministry of Education, Science and Sport and European Regional Development Fund

DURATION: 1.8.2016 – 31.7.2019