PayPal Holdings' ([[PYPL]] -1.7%) move to allow U.S. customers to sell, buy and hold cryptocurrencies depended first on a years-long effort to recruit the right talent with expertise in the relatively young field of blockchain.Also key to the effort: working with a trusted regulatory technology provider and having executive-level support, Edwin Aoki, chief technology officer for PayPal Blockchain, Crypto and Digital Currencies, told the Wall Street Journal.In October, PayPal was the first company to get a conditional BitLicense from the New York State Department of Financial Services.In 2016, crypto entrepreneur Wences Casares joined PayPal's board and started discussing with PYPL CEO Dan Schulman the potential for digital currencies to bring more people into the financial system.The company assembled a research group dedicated to explore blockchain by late 2017. The team at first focused on fundamental research related to blockchain, without specifically concentrating on how PayPal could eventually use the digital