Earlier this year the U.S. Patent Office issued a patent for a bar code/tatoo that could be applied to human flesh for the purpose of scanning in order to facilitate a financial transaction. From the abstract of patent 5,878,155:
A method is presented for facilitating sales transactions by electronic media. A bar code or a design is tattooed on an individual. Before the sales transaction can be consummated, the tattoo is scanned with a scanner… Once verified, the seller may be authorized to debit the buyer’s electronic bank account in order to consummate the transaction. The seller’s electronic bank account may be similarly updated.