A software vendor provides routine functionality and security updates to its global customer base.

Code signing uses cryptographic digital signatures to prove that software or updates come from a trusted source and have not been altered. In the SecurityX CAS-005 objectives, this is covered under security engineering and cryptographic assurance mechanisms.

Envelope encryption protects confidentiality but does not authenticate the source.

File integrity monitoring detects file changes but does not confirm the origin of the update.

Application control manages which software can run but does not ensure authenticity of distributed files.Only code signing meets all three objectives: verifying the source, ensuring authorization, and proving integrity.