Sign and Verify a Linux .so File Using OpenSSL

Updated Aug 31, 2026

Reported In

Software

  • LabVIEW

Issue Details

I need to use OpenSSL to digitally sign a Linux .so shared library. I also need to verify the signature before loading the .so file in LabVIEW. How can I implement this?

Solution

OpenSSL creates a detached signature, so the original .so file remains unchanged and a separate signature file is generated.

  • Sign the shared library with OpenSSL by typing this command: openssl dgst -sha256 -sign private_key.pem \ -out your_library.so.sig your_library.so
  • Verify the signature with OpenSSL by typing this command: openssl dgst -sha256 -verify public_key.pem \ -signature your_library.so.sig your_library.so

If the verification is successful, OpenSSL returns: Verified OK

If the file has been modified or the signature/public key does not match, the verification will fail.

Please note that Linux and applications such as LabVIEW do not automatically verify OpenSSL signatures when loading a .so file. If signature validation is required, your application must explicitly perform the verification before loading the shared library.

For more information, please refer to the OpenSSL documentation.