Security vs. Test Quality: Are they mutually exclusive?

A generally held opinion in the industry is that scan technology carries the potential of being misused to access proprietary design information, presenting a security risk to the semiconductor vendor's intellectual property (IP). For example, scan access can be used to learn something about the number of flip-flops in a design, which in turn indicates information about the performance-related blocks in the design. Scan access can also be used for fraud, where critical information is stored on the chip.