Matlab Runtime Compiler creates the .m files in the mcrCache

Dear community,

I created .exe files to deploy my .m files and share them to users outside my lab.

I used previously the 9.2 version but now I'm using the recent one (9.12).

In the cache folder ("C:\Users\useranme\AppData\Local\Temp\useranme\mcrCache9.12\), there are a lot of /m files created now for each executable launch.

I'm wondering if these files can be automatically deleted after the call?

I'm also want to be sure that these files do not share the code because it is confidential.

Best regards,

Sébastien

[Bruno Luong]

Have you notice that the mfile content is encrypted?

[Sébastien MAILFERT]

Yes, they are, but I am not convinced that they cannot be recovered by reverse engineering

[Bruno Luong]

I'm not awared any protection system that cannot be hacked.

But how deleting the files after run can reinforce the safety? It's so easy to make a copy of it.

May be -s option with an additional layer will make you think you are safer.

[Sébastien MAILFERT]

It's true!

I saw a previous comment saying this will slow down the next executions if you delete this cache folder each time:

https://fr.mathworks.com/matlabcentral/answers/101450-is-it-possible-to-automatically-delete-the-mcrcache-directory-created-by-a-matlab-compiled-executabl#comment_415597

[Bruno Luong]

Simply because it has to decrypt and expland into the cache folder everytime you run the code.

If you leave it there it do not need to do this two steps everytime. Just forget about the idea of deleting the cache, it hurts the execution without raise any significant level of protection.

[Sébastien MAILFERT]

Could you tell me how to use options in the Compiler toolobox GUI please?

"May be -s option with an additional layer will make you think you are safer"

Best regards, you helped me a lot!

[Bruno Luong]

I don't know, I use mcc commmand to build by app, and adding -s option is just straight forward.

[Sébastien MAILFERT]

The Mathworks support just replied me:

Thank you for getting back to us about this issue. In R2021b and R2022a Application Compiler Settings shows "Unknown flag(s) specified: -s", I verified it on my end too. This is a bug and our developers are working on fixing this for a future release. I am sorry I did not spot this bug in the first place.

I'm waiting for the next release...

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/matlab_prog/protect-your-source-code.html

Starting in R2021b, you can obscure the names of files and the directory structure, and also encrypt other file types (such as MAT, FIG, MEX, and so on) using the -s option for mcc (MATLAB Compiler). At run time, the encrypted files remain encrypted on the disk but are decrypted in memory to what they originally were before compiling.

[Sébastien MAILFERT]

Thanks, this should be the solution.

I see this option but I don't how to use it on the Compiler toolbox (there is an error)

[Sébastien MAILFERT]

The Mathworks support just replied me:

Thank you for getting back to us about this issue. In R2021b and R2022a Application Compiler Settings shows "Unknown flag(s) specified: -s", I verified it on my end too. This is a bug and our developers are working on fixing this for a future release. I am sorry I did not spot this bug in the first place.

I'm waiting for the next release...