Cryptocurrency exchange startup Coinbase has been awarded a new patent related to private key security, public records show.

The U.S. Patent and Trademark Office (USPTO) published the patent yesterday, entitled “Key ceremony of a security system forming part of a host computer for cryptographic transactions.” Two former Coinbase engineers – James Hudon, who now works for Uber, and Andrew Alness, currently employed at Keybase – are listed as inventors.

At its heart, the patent concept relates to a method for storing and utilizing bitcoin private keys. Coinbase has filed other patents in the past related to private key security.

As the patent document explains:

“A key ceremony application creates bundles for custodians encrypted with their passphrases. Each bundle includes master key share. The master key shares are combined to store an operational master key. The operational master key is used for private key encryption during a checkout process. The operational private key is used for private key decryption for transaction signing in a payment process. The bundles further include TLS keys for authenticated requests to create an API key for a web application to communicate with a service and to unfreeze the system after it has been frozen by an administrator.”

Public records indicate that the patent is the fourth to be awarded to Coinbase to date, and is one of a number of concepts the startup has moved to protect. The application for the “key ceremony” patent was originally submitted in May 2015.

Disclosure: CoinDesk is a subsidiary of Digital Currency Group, which has an ownership stake in Coinbase.

Key image via Shutterstock