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+# Vanguards-Lite
+
+Vanguards-Lite is meant for short-lived onion services such as OnionShare, as
+well as for onion client activity.
+
+It is designed for clients and services that expect to have an uptime of no
+longer than 1 month.
+
+## Design
+
+Because it is for short-lived activity, its rotation times are chosen with the
+Sybil adversary in mind, using the [max(X,X) skewed
+distribution](./vanguards-stats.md#MaxDist).
+
+We let NUM_LAYER2_GUARDS=4. We also introduce a consensus parameter
+`guard-hs-l2-number` that controls the number of layer2 guards (with a
+maximum of 19 layer2 guards).
+
+No third layer of guards is used.
+
+We don't write guards on disk. This means that the guard topology resets
+when tor restarts.
+
+## Rotation Period
+
+The Layer2 lifetime uses the max(x,x) distribution with a minimum of one day
+and maximum of 22 days. This makes the average lifetime of approximately two
+weeks. Significant extensions of this lifetime are not recommended, as they
+will shift the balance in favor of coercive attacks.
+
+From the [Sybil Rotation Table](./vanguards-stats.md#SybilTable),
+with NUM_LAYER2_GUARDS=4 it can be seen that this means that the Sybil attack
+on Layer2 will complete with 50% chance in 18\*14 days (252 days) for the 1%
+adversary, 4\*14 days (two months) for the 5% adversary, and 2\*14 days (one
+month) for the 10% adversary.