How does blockchain help to securely share data?

According to this news article at CoinDesk, the US Navy wants to connect their 3D printers to a blockhain to securely share their data throughout the manufacturing process?

Anyone have any idea how this concept will work? What is the 'transaction' that the blockchain will process, what are the 'rewards' for mining, etc? And how is this any different from connecting those printers in a secure intranet?