I was downloading a ISO file from Ubuntu and was just curious on some security questions concerning this process and after the download process. If I'm downloading a file can my file be infected while it's downloading? For example if someone else it browsing on a malicious site on my network and some malicious code spreads throughout my network, can a virus/malware infect my download? Lastly after my download is finished if I confirm the iso hashes and verify the hash files with their gpg key does this guarantee that my download was not infected whatsoever. If a virus did infect my download while it was downloading or if I downloaded from a malicious or unofficial link would the hases be different? This may be a stupid and paranoid heavy question but it just crossed my mind so I'd though I'd ask. Thanks!