This is old and not the one I read, but what I could find through search:
> Engineers needed manufacturing process information to verify that designs were free from systematic yield limiters, but foundries were reluctant to distribute process information that could reveal best practices and trade secrets. Encryption enabled the protection of selected design rules, process data and other information while still giving customers the details they needed.
> In this discussion, you must understand that the required protection is much more than just an obfuscation of rule definitions so they are no longer human readable. The process also includes the encryption of related files and control over all the outputs from the tool environment that provide information about any checks.
> Engineers needed manufacturing process information to verify that designs were free from systematic yield limiters, but foundries were reluctant to distribute process information that could reveal best practices and trade secrets. Encryption enabled the protection of selected design rules, process data and other information while still giving customers the details they needed.
> In this discussion, you must understand that the required protection is much more than just an obfuscation of rule definitions so they are no longer human readable. The process also includes the encryption of related files and control over all the outputs from the tool environment that provide information about any checks.
https://www.techdesignforums.com/practice/technique/protecti...
The design rules themselves could yield info to competitors about what processes are being used in the upcoming gen.