add note about timing analysis

1 files changed, 2 insertions, 1 deletions

diff --git a/22.md b/22.md
index 02ff3ab..28dc420 100644
--- a/22.md
+++ b/22.md
@@ -45,7 +45,7 @@ A sender publishes a series of `kind:2444` or `kind:20444` where the `payload` i
 
 Event `kind:2444` has the exact same format as the `kind:20444`, the only difference being that it's not ephemeral, so it can be used to route events that are expected to take longer to route. `kind:2444` events SHOULD include an [[NIP-40]] `expiration` tag.
 
-Routing pubkeys MUST look at the `created_at` of the event they need to publish and wait until at least that time before publishing.
+Routing pubkeys MUST look at the `created_at` of the event they need to publish and wait until at least that time before publishing. Using future `created_at`s allows the sender to increase their privacy by preventing timing analysis by mixing different time delays at each hop.
 
 When a routing pubkey receives a routing request event it should decrypt the content, redeem the cashu and publish the event in the `event` field. If the cashu cannot be redeemed the routing pubkey MUST NOT publish the event. This is useful as a way to **cancel** a routing event where the sender uses a future `created_at` timestamps and chooses to cancel the publication.
 
@@ -139,3 +139,4 @@ function assemble_onion_route(final_event, path) {
     }
 }
 ```
+