For the operators of a website, storing that information is a challenge of its own, but it’s only half the battle. First, one must get the customer to offer that information, and for them to have the peace of mind that in giving that information to someone, that the recipient of it will treat that data with the security that it rightly deserves.
Of course, a visitor to a website has no idea how the data is stored by the website operator, they have to take that bit on trust that it is done correctly, but a huge step in demonstrating to a website visitor that a company is worthy of their trust is to establish their connection over an SSL (Secure Sockets Layer) connection.
SSL certificates are easy and relatively inexpensive to obtain; they are incredibly simple to install and take almost no time to obtain. For this small investment in effort, one can give their users the peace of mind that they increasingly require in today’s heavily data-dependent world.