> Notice how this article never clearly states specifically how a block chain solves the supply chain problem

Oh, I noticed. In fact it's the first thing I go looking for in these articles about "blockchain solves problem X".

And then I read the words "IBM Hyperledger". I've tried to find out what Hyperledger is, but penetrating IBM's blizzard of marketing bullshit about it has so far proved beyond me. All I know it has some relationship to a think called a "permissioned blockchain".

From what I can gather (as it is also surrounded by a cloud of marketing hype) a permissioned blockchain doesn't use proof of work, proof of stake or anything related. Nor is there a race to append the block. (Thus is it prompted as solving bitcoin's energy "problem", and because it doesn't need time to accumulate the proof of work it's not limited in the number of transactions it can process). Instead a permissioned blockchain appoints (ie, gives permission to) some miners to process the blocks. I have no idea what happens next, but I'm guessing in practice there is only one miner who checks the incoming transactions and assembles then into a block, signs the block using a public key, and publishes it by appending it to the database where it remains unchanged forever more.

To me the word blockchain doesn't just mean "append only published database". If that was true every log file would qualify as a blockchain. It also involves a clever set of rules for appending to that database that have one clear goal: they ensure the log is append only by making alterations computationally expensive.

In doing that a blockchain makes the "trust" quantifiable, eg to rewrite an entry 24 hours old in the log you are going to have to expend roughly 100 G Watt hours. Then by using more magic (the consistency checks aren't just rules, they are computer programs that can include assertions on future events, and thus control what happens in the future), the assertions can extended into "I promise to do X in the future, and if I don't I loose Y", and the only way to undo that promise is to expend that 100 G Watt hours.

A permissioned blockchain shares none of those properties, so to me it isn't a blockchain name notwithstanding. What it does look like is the old fashioned titles office - if I want to transfer my house title I have to give a notice to the Titles Office, and when they give it their official stamp of approval and append it to their records, and it's done. In that case the currency is property, the transactions are record of change of ownership of that property (which always originate with the state owning the land), the blockchain database is the records of all changes of ownership (which happens to be public in this case), the single miner is the Titles Office.

The amount of trust you have in the system boils down to much you trust the Titles Office to do its job (are they easily fooled, can someone be bribed, could a fire destroy the chain, and so on). This is not easily quantifiable. As an example I live in Australia whose civil systems are about as strong as you can get, yet every few years we have a new headline of someones house being sold from under them (usually while they were on an extended overseas holiday) due to title fraud. There is no recourse when this happens - the transaction is as irreversible as a bitcoin transaction and the state have legislated to ensure they are not responsible for any losses. However unlike bitcoin, it's impossible to extend the trust you put in the Titles Office to other applications. Or to put it another way: they are not going to look after your Ethereum ICO's for you, whereas Ethereum could do a very good job of looking after titles.

So it isn't a blockchain. It looks to me like IBM is selling "Titles Office" software for other applications, given it the fancy name "Hyperledger" and added blockchain to marketing blurb for extra pizzazz. 10 points for marketing prowess I guess.

It does however sound like a reasonable way to track food supplies. The currency is the food with some certifications. The transaction are changes of ownership, the miner is someone appointed to collects the sad transactions, stamp them as official, and append them to the log, the database is public so everyone (including the state and consumers) can verify everyone has made the right promises on that strawberry they are eating so they can sue there arses off if it contains needles. And the entity doing the certification (IBM?) gets to make a bit of money for their efforts.