What is a DLL.SIG file? A DLL.SIG file is a digital signature associated with a specific .DLL file. It is used to verify that the DLL file is authentic and has not been modified by anyone other than its developer. Various Windows apps that include DLL files also include accompanying DLL.SIG files.

More Information DLL files are Dynamic Link Libraries, which Windows programs use to access procedures and drivers. For example, a Windows program might use a DLL file to communicate with external devices or read and write certain files. Some programs' DLL files are accompanied by DLL.SIG files. These files typically have a similar filename as their associated DLL files. For example, the Windows version of Google Chrome includes a DLL file named widvinecdm.dll and a DLL.SIG file named widevinecdm.dll.sig . Each DLL.SIG file contains a digital signature that an app developer generated using a private cryptographic key. The app uses this digital signature to verify that the associated DLL has not been tampered with, before using the code stored in that DLL.