eBay's PayPal is in talks with Coinbase and other bitcoin transaction providers to integrate the virtual currency within its Braintree payments system, The Wall Street Journal reported on Thursday. Executives at PayPal, which owns the service that handles payments for startups from room-bookings network AirBnB to car-on-demand service Uber, have not struck any agreements, the Journal cited people familiar with the matter as saying. A deal would be an endorsement for a crypto currency, which is gaining acceptance with a slowly growing number of businesses, including online retailer Overstock.com. But some industry executives have warned about the risks of an unregulated currency. Ebay bought Braintree for $800 million in 2013 to boost PayPal's mobile presence.