The digital signature mechanism checks validity and integrity of software packages to ensure that the software installed on a device is secure and reliable.
After a software package is released, it has security risks, such as the software package components being replaced or tampered with, in the transfer, download, storage and installation phases. A digital signature is packed into a software package before it is released and validated before the software package is loaded on to a device. The software package is considered complete and reliable for further installation and can be used only after the verification on the digital signature succeeds.
Digital signatures are verified when you set the patch or system software package for next startup, or install a patch.