docs: init middleware docs

docs/middleware/deniability.md

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+# Deniability Middleware
+
+This package provides the PreHook `deniability` which inserts ghost peers into announce responses and increases scrape counters to achieve plausible deniability.
+
+## Functionality
+
+### For Announces
+
+This middleware will choose random announces and modify the list of peers returned.
+A random number of randomly generated peers will be inserted at random positions into the list of peers.
+As soon as the length of the list of peers exceeds `numWant`, peers will be replaced rather than inserted.
+
+Also note that the IP address for the generated peeer consists of bytes in the range [1,254].
+Whether IPv4 or IPv6 addresses are generated depends on the announcing Peer's IP.
+
+Note that if a response is picked for augmentation, at least one Peer will be inserted.
+There is one exception to this rule:
+Otherwise empty reponse will not be augmented to make it more difficult to determine the prefixes used for generated Peers.
+
+### For Scrapes
+
+A scrape will randomly be chosen, based on the `modify_response_probability`.
+If chosen, a number of seeders and leechers will be generated for every InfoHash of the scrape.
+
+Note that there will be at least one peer added to every InfoHash, this can be either a seeder or a leecher.
+As with Announces, the only exception to this rule are otherwise empty scrapes.
+
+## Configuration
+
+This middleware provides the following parameters for configuration:
+
+- `modify_response_probability` (float, >0, <= 1) indicates the probability by which a response will be augmented.
+- `max_random_peers` (int, >0) sets an upper boundary (inclusive) for the amount of peers added.
+- `prefix` (string, 20 characters at most) sets the prefix for generated peer IDs.
+    The peer ID will be padded to 20 bytes using a random string of numeric characters.
+- `min_port` (int, >0, <=65535) sets a lower boundary for the port for generated peers.
+- `max_port` (int, >0, <=65536, > `min_port`) sets an upper boundary for the port for generated peers.
+- `parallelism` (int, >=0) determines the amount of parallelism this hook can operate with.
+    The resulting theoretical upper limit of parallelism is `2^parallelism)`, assuming an even random distribution of infohashes.
+
+An example config might look like this:
+
+```yaml
+chihaya:
+  prehooks:
+    - name: deniability
+      config:
+        modify_response_probability: 0.2
+        max_random_peers: 5
+        prefix: -AZ2060-
+        min_port: 40000
+        max_port: 60000
+        parallelism: 8
+```
+
+For more information about peer IDs and their prefixes, see [this wiki entry](https://wiki.theory.org/BitTorrentSpecification#peer_id).

docs/middleware/interval_variation.md

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+# Announce Interval Variation Middleware
+
+This package provides the announce middleware `interval variation` which randomizes the announce interval.
+
+## Functionality
+
+This middleware chooses random announces and modifies the `interval` and `min_interval` fields.
+A random number of seconds are added to the `interval` field and, if desired, also to the `min_interval` field.
+
+Note that if a response is picked for modification and `min_interval` should be changed as well, both `interval` and `min_interval` are modified by the same amount.
+
+## Use Case
+
+Use this middleware to avoid recurring load spikes on the tracker.
+By randomizing the announce interval, load spikes will flatten out after a few announce cycles.
+
+## Configuration
+
+This middleware provides the following parameters for configuration:
+
+- `modify_response_probability` (float, >0, <= 1) indicates the probability by which a response will be chosen to have its announce intervals modified.
+- `max_increase_delta` (int, >0) sets an upper boundary (inclusive) for the amount of seconds added.
+- `modify_min_interval` (boolean) whether to modify the `min_interval` field as well.
+
+An example config might look like this:
+
+```yaml
+chihaya:
+  prehooks:
+    - name: interval variation
+      config:
+        modify_response_probability: 0.2
+        max_increase_delta: 60
+        modify_min_interval: true
+```