American Express is on the hunt for better ways of proving when transactions occur and a new patent filing suggests the financial services giant may be looking at blockchain as part of a possible solution.

In a patent application released by the U.S. Patent and Trademark Office last week, American Express Travel Related Services describes using a “blockchain-based system” in order to receive “payment confirmation including a transaction amount and a merchant identifier.”

The concept is aimed at adding to what AmEx calls the “limited” number of options for generating quality evidence that payments happen between merchants and their customers “beyond a receipt or ticket.

AmEx’s patent highlights the tech’s role in retaining “transaction data, contract data, proof-of-payment data, identification data, and/or other information as desired,” with the idea being that a blockchain network – possibly a public one – would serve as an extra layer of proof for transactions that take place on AmEx’s network.

As a result, the potential applications of such a system are quite varied, the company contends.

American Express says that data can be used to “unlock a hotel, rental or shared economy property door using the card (e.g., that was used for the payment) to look up proof of payment on a blockchain.” Moreover, “the system may be leveraged to provide ticketless access to venues (e.g., movie theater, sports event, concert, etc.) to a customer,” and so forth.

While the decision on whether this blockchain system will be hosted on a private, public or consortium network is up for grabs, the application does highlight how “public networks may leverage the cumulative computing power of the network to improve security.”

This patent application by American Express is the latest in a series that have been launched as early as October of last year when the same branch of the company filed for a different patent related to customer rewards.

Fast forward to today and the company has indeed begun initial trials with a custom Membership Rewards program for cardholders, leveraging Hyperledger’s blockchain technology, which it partnered with last January.

Payment terminal image via Shutterstock