Then, last year, IBM executives flew to Walmart's headquarters in Arkansas to propose a solution: the blockchain.
As Mr. Yiannas studied their pitch, he said, "I became increasingly convinced that maybe we were onto the holy grail."
The blockchain — the buzzy, bewildering technology behind cryptocurrencies like Bitcoin — is starting to be applied to real-world problems like tracking pork chops, shipping containers and footwear with a speed and security not currently possible. The IBM-Walmart partnership is one of the biggest practical tests to date.
At its heart, blockchain simply refers to a bookkeeping method that "chains" together entries so that they are very difficult to modify later. It provides a way for large groups of unrelated companies to jointly keep a secure and reliable record of their transactions.
