Hello Kyrillos,
First of all, encrypted files are used all the time with IPs from different vendors; you can encrypt an RTL file of your choice and use it in both simulation and synthesis just to get a feel of how encrypted (or as Synopsys call them, protected) files are used.
Encrypted files are recognized by DC and VCS, just read them:
Code:
vcs top.v top_tb.v enc.vp
./simv
On encrypting a file, you are provided with plenty of options, to mention a few:
1- Encrypt only the body of the module (leave the module interface visible).
2- Encrypt the file to be only used within Synopsys tools.
3- Encrypt the file
to be used only in simulation (say, a vendor wants to release an IP for simulation only and you need another license to synthesize it).
You must always ask if the encrypted file provided to you can be used "during synthesis" and "is it compatible with Synopsys tool".
Hope this made things a bit clear.