I'd like to sign my executable files on an air-gapped machine. Problem is, the code-signing tools for OS X and Windows (ie. codesign and signtool.exe) seem to

I'd like to sign my executable files on an air-gapped machine. Problem is, the code-signing tools for OS X and Windows (ie. codesign and signtool.exe) seem to require access to my private key to generate the signature AND and an internet connection to generate the timestamp. Is there any solution here?