Blockchain is a relatively new (2008) computational process that provides security for financial (and other) transactions. How it all works is a bit beyond me, but this is the first paragraph on it at Wikipedia:
A
blockchain is a growing list of
records, called
blocks, that are linked together using
cryptography. Each block contains a
cryptographic hash of the previous block, a
timestamp, and transaction data (generally represented as a
Merkle tree). The timestamp proves that the transaction data existed when the block was published in order to get into its hash. As blocks each contain information about the block previous to it, they form a chain, with each additional block reinforcing the ones before it. Therefore, blockchains are resistant to modification of their data because once recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks.
Basically, each block in the chain has the hash of the previous, such that no block can be changed without every block having to be adjusted all the way back to the origin. It was originally for crypto currency, to assure the true value of a bitcoin was not tampered with by anyone who had held it. The data is spread by peer-to-peer networks, so there is no single point at which a bad actor can amend the data and not have it noticed. In terms of asset management, rather than bitcoin, a business can track product from source to destination securely. So a coffee company can buy coffee from a grower, track that coffee from the grower to the shipper to the importer to the roaster to the packager and know, beyond reasonable doubt, that the beans in THIS bag came from THAT farmer. The value of such traceability may not be there for coffee, but for other vegetables that may have a risk of contamination, for example lettuce and spinach, the product can be traced from field to market, such that if there is a contamination, every leaf of that contaminated field can be found and identified accurately.
Imagine a public ledger that is copied into every accountant every time a transaction is posted. If anybody tries to change an entry later on to defraud anybody, that person would have to get to every copy of the ledger everywhere. Now, if each page has a hash calculated from all of the transactions on each page, based on the hash of the previous page and what transactions are posted in what order on the next, the hash will be wrong as soon as the change is made, and won't match the hash on any of the other ledgers. Basically, that's the simplest way to see it.
You can read more on Wikipedia:
Blockchain - Wikipedia
