ISC2 Systems Security Certified Practitioner (SSCP) Practice Question

Digitally signing the firmware with the organization's private key allows any device holding the corresponding public certificate to verify both the origin (authenticity) and that the code was not altered (integrity). Confidentiality is not required, so the file can remain publicly downloadable. AES encryption with a shared symmetric key would provide confidentiality but requires securely distributing a secret to every device and does not provide non-repudiation. Publishing an MD5 checksum supplies integrity verification but cannot prove the publisher's identity and relies on a weak hash algorithm. Using SSH tunnels would add transport protection, but it negates the use of a public CDN and still would not provide proof of origin once the file is stored locally.