How to find "file signature" of design files in Cadence Virtuoso (schematics, layouts, symbols, etc.)

Hello colleagues,

I am trying to recover the  lost files (design files such as schematic, layout, symbol) using Cadence Virtuoso IC6.1, I have to determine these "files' signature" for my partner to recover these data.

That is to say, to recover these data, I should know the file signature of the schematics, layouts, symbols of the block that I designs.

Any experience on this, or any hints, recommendations from you are highly appreciated.

Thank you very much!