By Gertrude Chavez-Dreyfuss NEW YORK (Reuters) – One of the leading European-based bitcoin exchanges is adding another virtual currency to the bitcoins already traded on its platform. Ripple, a U.S.-based provider of blockchain-based banking payments technology, said on Tuesday its digital currency XRP will start trading on Bitstamp on Jan. 17. In a blog posted on Ripple’s website, the company said the XRP/euro and XRP/dollar currency pairs will be available to all customers and regions currently supported by Bitstamp.