In public key cryptography, code signing is a specific use of certificate-based digital signatures that enables an organization to verify the identity of the software publisher and certify the software has not been changed since it was published.
Digital signatures provide a proven cryptographic process for software publishers and in-house development teams to protect their end users from cybersecurity dangers, including advanced persistent threats (APTs), such as Duqu 2.0. Digital signatures ensure software integrity and authenticity. Digital signatures enable end users to verify publisher identities while simultaneously validating that the installation package has not been changed since it was signed. All modern operating systems look for and validate digital signatures during installation, and warnings about unsigned code can cause end users to abandon installation.