The latest rage is all about the block chain, made popular by Bitcoin. It’s not exactly authentication but more publication of data in a sense that it becomes part of a sequential public record. From that point on, it can be looked up and verified.

The clever part is that the public record isn’t posted in a particular place or location but is distributed all over, approximately to everyone who cares. Since everyone has a copy, they can be verified against each other.

As pointed out in the article below, it’s like publishing a snippet about a transaction in a newspaper which is then sent out to all subscribers. In this case, though, the newspaper contains all of the transactions ever published there and just keeps adding to them. You can see one of the first problems right there. This growing “ledger” just keeps, well, growing. It doesn’t seem to scale well as they say.

How the blockchain will enable self-service government by Brian Forde and Michael Casey of Wired UK.