Just kidding. It’s not that simple but the BBC News has this interesting story about a new method of authenticating art works:

The approach, known as “sparse coding”, builds a virtual library of an artist’s works and breaks them down into the simplest possible visual elements. Verifiable works by that artist can be rebuilt using varying proportions of those simple elements, while imitators’ works cannot. The work is reported in Proceedings of the National Academy of Sciences. […]

• Each of an artist’s works is cut into 144 pieces (12 rows and 12 columns)

• A set of 144 random elements the size of each piece is generated

• Each element is altered by a computer until some combination of them can recreate each piece from the original artwork

• The elements (shown above) are refined until the fewest are required to recreate each piece

• Those refined pieces will be unable to reproduce the work of an imitator or a fake

The team tried the approach on the works of Pieter Bruegel the Elder, a 16th century Flemish painter whose original works are well-known and who had a number of imitators.

[…] However, Professor Rockmore said that although authentication of works was an application that would appeal to many people, sparse coding could lend its analysis to a number of problems in the study of art. “Our hope is that it becomes more of what people call technical art history,” he told BBC News. “Instead of asking ‘was this painting done 40 years after these drawings?’, one might instead ask ‘how are these statistics evolving over time and what does that say about the working style?’.For many people those are more central questions, and probably more substantial questions.”

Computer Method Spots Art Fakes (BBC News)