All eyes might be on marijuana right now, with Canadian legalization just two days away, but it's blockchain technology that could actually create more buzz over the long term. 

If you're unfamiliar with blockchain technology, we're talking about the ability to securely and quickly move money from Point A to B, as well as store massive amounts of data in an immutable (i.e., unalterable) way. In plainer English, blockchain could do everything from expediting the validation and settlement of payments in the financial sector, to improving supply chain efficiency by eliminating paper trails for retailers, shipping and trucking companies, pharmacies, and a slew of other businesses. It's this dynamic aspect of being able to help the financial system and nonfinancial industries that makes it so appealing.

With that being said, we asked three of our Foolish contributors to name a blockchain stock that they believe is worth closely monitoring in October. Making the grade were credit services behemoth American Express (NYSE:AXP), networking kingpin Cisco Systems (NASDAQ:CSCO), and consulting megacap Accenture (NYSE:ACN).

A businessman touching an encrypted block on a digital screen that's part of a larger blockchain.

Image source: Getty Images.

This stodgy Dow stock is revolutionizing the application of blockchain 

Sean Williams (American Express): I believe the thing that's most interesting about the blockchain revolution is that it's being led by the oldest, stodgiest companies in existence. Last month, I suggested keeping a close eye on IBM, and in October I believe it prudent to give a closer look to credit services provider American Express.

What the heck could American Express, a company best known for courting affluent spenders, want with blockchain? Well, to begin with, blockchain could help AmEx move money from Point A to B in rapid and secure fashion. Since American Express is regularly dealing in cross-border transactions, and blockchain offers the promise of validating and settling these transactions in a fraction of the time it takes today's banking networks to do so, it could hold value.

For example, American Express has been working with Ripple and Banco Santander for nearly a year now on a pilot program whereby payments can be made over AmEx's FX International Payment network to U.K. Santander accounts in almost real time. In theory, this partnership and blockchain network could prove scalable over time.

But even more so than just payment expediency, American Express probably relishes what blockchain can do for immutable data storage. Back in the spring, AmEx launched a blockchain for membership rewards, thereby allowing merchants within its network to offer rewards on their own channels (i.e., apps and websites), rather than solely through the company's channels.

What makes this approach so intriguing is that it could allow retailers the opportunity to see if promotional activity actually leads to meaningful sales thanks to the immutable recordkeeping of blockchain. Similarly, it would allow AmEx access to sought-after retail-level data that it could use to reach more merchants and consumers. 

Though it may still be a few years before American Express sees the needle move from its investment in blockchain, it's certainly established itself as a prime player.

A smart city connected to the internet of things, as represented by blue dots scattered throughout the city.

Image source: Getty Images.

Blockchain and a lot more

Keith Speights (Cisco Systems): Cisco Systems provided key technology that helped fuel the internet boom in the 1990s. Can this established technology company lead in the blockchain boom that's underway, too? I think so.

Like several other tech giants, Cisco has jumped into blockchain head first. The company is developing a blockchain platform that interfaces with other systems and includes end-to-end security and analytics. Cisco helped found the Trusted IoT Alliance, an organization that includes both big companies and small start-ups with a focus of addressing the challenges of using blockchain with the Internet of Things. It has also joined several other groups seeking to move blockchain technology forward. 

Of course, Cisco focuses on a lot more than just blockchain. The company's bread and butter through the years have been its switches and routers. But Cisco is well on its way to converting from a business primarily based on hardware sales to one with steady recurring revenue from subscriptions for its products and services.  

Investors have several reasons to like Cisco stock. The company's earnings are growing nicely as its shifts to the recurring revenue model. Its dividend yields nearly 2.8%. The company has an enormous cash stockpile -- $46.5 billion at the end of Q2 -- that it can use to reward shareholders and fund acquisitions. There are certainly more pure-play blockchain stocks, but I think Cisco ranks as a top stock to watch in the space.

A businessman staring at an encrypted blockchain on a digital screen.

Image source: Getty Images.

Betting on the experts

Brian Feroldi (Accenture): Blockchain is a fascinating technology that promises to transform the business landscape. Unfortunately, the technology is still so new that it isn't clear which companies will benefit or be harmed by its deployment. However, I'm quite confident that businesses that want to learn more about blockchain will eventually reach out to the experts for help. That's a ripe opportunity for consulting giant Accenture. 

Accenture is the go-to tech consultant for an impressive array of businesses. Roughly 95 of the Fortune Global 100 rely on Accenture for help with tech trends like cloud computing, data security, and digital services. Since Accenture spends lavishly to make sure that its army of employees are well versed in the latest and greatest tech, I'm sure it won't be long before blockchain is added to that list. 

For investors, adding blockchain knowledge to its tool belt should easily help the company to pull in more revenue from existing clients and convince new ones to sign up. That should enable its predictable revenue growth rates to continue. When adding in the company's consistent ability to improve margins, I believe high single-digit to low double-digit earnings growth is achievable for the foreseeable future. 

So what's management going to do with its growing profit stream? History shows that the proceeds will be used to grow the dividend -- which currently yields 1.7% -- and make tuck-in acquisitions. Those moves should create value for shareholders over time.

Best of all, this low-risk tech stock can be purchased today for less than 20 times next year's earnings estimates. I think that's a bargain price for this high-quality business.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.