All emerging technologies have opportunities and drawbacks, and 3-D printing is no exception.

The 3-D market is expected to grow exponentially. Industry analysts at IDC recently released their growth estimates; they say global spending on 3-D printing is expected to top $35 billion in 2020. If that projection is accurate, the 3-D printing market will already be a whopping 25 percent of the projected size of the global market for machine tools -- a highly mature industry -- in 2020.

The capabilities that 3-D printing provides also bring substantial security and economic threats. The interception or theft of the files going to 3-D printers provides all that is necessary to produce counterfeit parts. Also, consider the global implications associated with the production and sale of products based on theft of intellectual property.

Think about what would happen if the plans for one of the U.S. military's weapons system were stolen. And the threat does not stop with cyberattacks and espionage. Researchers at the University of California-Irvine's Advanced Integrated Cyber-Physical Systems Lab recently demonstrated that the acoustic signals emitted by a 3-D printer convey unique information about the precise movements of the printer's printing nozzle

3-D printing is clearly another high-value target for physical and cyber espionage.