To Digitally Sign an AutoLISP File

AutoCAD-based programs use digital signatures to verify whether a custom program file can be safely loaded. AutoLISP files with the LSP, MNL, FAS, or VLX file extensions can be digitally signed.

A digital certificate must be installed on the machine before you can sign an AutoLISP file. See the topic "To Make a Digital Certificate" on making a digital certificate and the topic "To Import a Digital Certificate" to import a certificate.

Note: VLX files that are digitally signed cannot be loaded into AutoCAD 2015-based and earlier products. Create a backup copy of your VLX files before digitally signing them.

1. Click the Windows Start button Autodesk Attach Digital Signatures.
2. In the Attach Digital Signatures dialog box, click Add Files.
   Tip: Click Search Folders if all your AutoLISP files to signed are located in multiple folders.
3. In the Select File dialog box, browse to and select the AutoLISP file to digitally sign. Click Open.
   Tip: Press and hold the Ctrl key to select multiple files.
4. In the Attach Digital Signatures dialog box, under the Select A Digital ID (Certificate) section, select a digital ID.
5. Under the Signature Information section, click the Get Time Stamp From drop-down list and select a server or the local computer.
   Note: If the connection to the time sever fails, select a different server or the Time from This Computer item.
6. Optionally, in the Comment text box, enter a description as to why the file is being digitally signed.
7. Click Sign Files.
8. In the Signing Complete message box, click OK.
9. In the Attach Digital Signatures dialog box, sign additional files or click Close.
10. Load the newly signed file into an AutoCAD-based program and verify that the digital signature is recognized.

Note: Any changes to the AutoLISP file will result in the signature becoming invalid. Re-sign the file using the previous steps and when prompted to replace the digital signature, click Replace the Existing Signature or Replace All Existing Signatures based on the number of files you are digitally signing.