Put the readings in a secure database--on, say, a mainframe owned by the credit card issuer.

FORBES: Safety in Numbers

The FTC enters complaints into Consumer Sentinel, a secure, online database available to more than 2, 000 civil and criminal law enforcement agencies in the U.S. and abroad.

ENGADGET: FTC introduces changes to Children's Online Privacy Protection Act, parental permission now required to collect information

Hacking of accounts for Valve, Sony, (possibly) Diablo III and so on have demonstrated that no database is completely secure, and that players (and users of the Internet) need to account for the impossibility of protecting their data.

FORBES: League of Legends Hacked: You Know The Drill By Now

When the customer has used up all 100 keys in the database, he goes to a secure ATM-like machine that takes more laser readings at different spots and transmits the keys to the database.

FORBES: Magazine Article

You as a customer can use SQL and standard tools with Oracle applications, and the environment is secure (you can query, integrate, and backup the cloud at the database level, not the application level).

FORBES: Oracle Transformed - It's Now All about the Cloud