Unsigntool

Unsigntool is a small command-line tool that can remove digital signatures (certificates) from Windows PE (Portable Executable) files. Removing the certificate from PE file may come in handy if you need to re-sign the file with different certificate or if the certificate is invalid or outdated. Also modifying a signed file in any way will invalidate the signature and removing the certificate is a good idea to avoid bogus warnings or other unexpected problems. Give Unsigntool a try to fully assess its capabilities!