Metadata is the hard part

It's tempting to market a messenger on its encryption. But the Signal Protocol is, at this point, a settled science. The genuinely hard problems live one layer down: NAT traversal, offline delivery, and the metadata that leaks even when every byte of content is sealed.

Blink uses blind relays for store-and-forward, so a message can wait for an offline recipient without any server reading it. But a relay still learns that a sealed blob exists for someone, and roughly when it was collected. Sealed-sender hides the 'from'; batching blurs the 'when'. Neither makes the metadata vanish.

We could pretend otherwise. Instead we tell you: content is protected, network metadata is partially exposed, and if your adversary is a nation-state, you want Tor underneath. Honesty is a feature.