ActivityPub - Is it worth defending against replay attacks and message/signature time skew?

Here's a problem that I've found with ActivityBot - my little ActivityPub server. Sometimes it receives messages which were originally sent months ago. Why does that happen and is it risky to accept and process them? My tl;dr is that it probably isn't worth worrying about. But I'd love someone to tell me why I'm wrong. Here's my thinking: Table of ContentsCausesIs that a problem?What are we…

Source: https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.