Currently, It is not practical to store large scale data, including documents, on a blockchain. There are size and speed constraints and commercially available data encryption will not hold up against future attacks when quantum computers become readily available. However, blockchain hash functions, which act as digital finder prints, are thought to be attack proof. Feeding in data, such as a the text of the PDF of a contract, can be converted to a short hash string, which can be stored on the blockchain. If a single character is changed, the hash changes. There is no know way of reverse engineer the hash from the original text/data.
As a practical application, all contracts could be automatically hashed by a document management application and the hash would be registered on the Integra ledger. If two parties each produce a different copy of a PDF, claiming that it was the executed copy, the parties could hash both the documents and check against the record on the Integra Ledger. Only the legitimate copy would match proving which is the valid copy through this “Proof of Existence”.
NetDocuments integrated with Integra to show proof existence in a document management system.