On-Device Context: A defense against misinformation in the encrypted WhatsApp

We propose maintaining a list of rumors (including image, audio, and video hashes) along with corresponding fact-checks, similar to what Facebook uses when identifying misinformation in its news feed. This “context list” can be regularly supplied to WhatsApp clients, so that if someone receives a debunked rumor, WhatsApp can provide the relevant context or fact-check (similar to how WhatsApp currently flags suspicious links). The same list can also be used to warn people sending rumors in the first place.