I had just learned everything there was to know about the fish in front of me. Now a small part of its fleshy, red body was in my mouth. Five minutes earlier, I saw a video showing the waters in Fiji where it was caught, where it traveled on ice, and how exactly it ended up inside a sushi hand roll. The massive yellowfin tuna had been tracked across the globe via the Ethereum blockchain.

Each stop on the fish's journey, from the landing dock to the processing facility to the truck that drove it to Brooklyn, had been cataloged. The demonstration, organized by the startup Viant, was meant to showcase one of the potentially most compelling use cases for blockchain technology. A plethora of startups—as well as major companies like IBM and Walmart—are betting that the tech will change the way goods travel around the world.

A blockchain is essentially a distributed chain of data entries that everyone can view and that can't be easily altered. In other words, blockchains are digitized, more secure versions of the ledgers that merchants and traders have relied on for thousands of years.

For now, the technology is still in its infancy. The industry around blockchains is riddled with scams, false promises, and has been met with a heaping load of skepticism. Many of the "problems" to which its evangelists have tried to apply it don't make much sense, like bacon, iced tea, and ending bullying.

But supply chains appear to be a legitimate use case for the technology, tracking materials as they move around the globe. There are promising signs, but also serious hurdles to deploying blockchain tech broadly in logistics. It likely will be years, if not decades, before that happens.

For one thing, during Viant's demonstration, which took place at the Ethereal Summit, my phone was blowing up with emails. The messages, from United Parcel Service, alerted me to the exact location of a package I was expecting. It's hard to understand, at least at first, how a fancy new technology could make that system better.

One Shipment of Avocados

But Kishore Atreya, a cofounder of Viant, the startup behind the fish demonstration, says the current supply-chain system is limited. Tracking tech like UPS’s reflects only the data that matters to UPS. "In the package example you have cited, the customer gets only the logistics view and history, but not a holistic view of the product—its ingredients, source, processing, etc.," he says.

It’s hard, if not impossible, to learn where the sweater you're wearing or coffee you're drinking really came from. Shipping a container of avocados from India to the Netherlands, say, involves dozens of people and businesses. Farmers need to drop off the avocados, boats need to pick them up, regulators need to sign off on the container’s contents, and someone needs to make sure that the fruits haven't gone bad. Most of these handoffs and communications are still done via analog technology.

LEARN MORE The WIRED Guide to the Blockchain

"There are so many parties involved, up to 30 different parties are all touching one container and they're just waiting for each other to communicate information," says Christiaan Sluijs, the CFO of T-mining, a Belgium-based blockchain logistics company. He adds that many corporations still use paper to handle necessary documentation like certificates of origin, invoices, insurance policies, and bills of lading. All that paperwork is estimated to account for one-fifth of the total transportation costs, according to IBM. "That's a bit stupid because you can send that information in a digitized way," says Sluijs.

That's where blockchain technology comes in. The idea is to create a digitized version of the paperwork and allow everyone in the supply chain to know where a shipment is located. That system might live inside a mobile app, and involve other tech, like QR codes, cameras, RFID chips, or internet-connected sensors.