Visa has published best practices for data field encryption (AKA end-to-end encryption) that call on merchants to always encrypt cardholder data.
Data field encryption covers techniques for ensuring swiped credit data is always stored and transmitted in an encrypted format right from the point where a customer plastic is swiped or an online order is taken. The approach is designed to supplement existing PCI DSS security standards for merchants in helping to protect cardholder data from hacking attacks, particularly those targeted at retailers or online merchants.
