Index Ai Academy
Glossary · Phase 8 · APIs

Replay attack

Also written: replay attacks

Recording a genuine message and sending it again later. Signed timestamps defend against it.

Including the time in what's signed blocks replay attacks. An attacker who copies one real webhook could otherwise resend it forever, like photocopying a valid ticket. You reject any message whose t is more than a few minutes from now.

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Delivery is at least once. Handling the same event twice must do no harm.

Learn it properly

Webhooks and events · Push events to other systems: signed, retried and deduplicated. About 40 minutes.

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