Blockchain is the solution, now what was your problem?
I understand the concept and technology behind Blockchains. It is an interesting way to handle transactional data where the audit log has to be inviolate. It works very well where there is a contract of some sort (I sell you some medical records, you provide me with some money).
But as a way to exchange sensitive information? I just don't get this. For a start, medical records are large. Huge. Especially if they have scans that need to be transferred. This is not a suitable use of a blockchain;
Then there is the distributed nature of the information. Yes, it's great against failure provided you have enough participants. But it does mean that anyone who can join the chain can request to see anything that they want. So, the data needs to be encrypted against unauthorised access. So, now you have the issue of key management and key distribution. In the meantime, I can see the data, albeit encrypted, and I can start cracking it.
Or is that what they are actually doing: making the encrypted data available, and then sending the key, itself encrypted, via blockchain. Now that might actually make some sense, as now we have a record of who has seen the keys. Using blockchain as an audit.
Honestly, this all sounds as though IBM have a solution and now every problem they come up against needs a blockchain as a solution.
It used to be that the solution was IMS; then it was DB2; then it was MQ-Series; now its blockchain.
Or am I being overly cynical?