Links are checked by reading the address only. The Shredder never opens them, and the lookup buttons open VirusTotal or Google, not the link itself. Files are checked on your phone and never uploaded. The deep scan looks through every byte for hidden programs, scripts, and extra data. "Check on VirusTotal" looks up only the file's fingerprint against about 70 antivirus engines. Brand-new malware nobody has reported yet can still slip through. Delete amber and shredded files from Files or Telegram yourself.