Add AES encryption between nodes

README.md

@@ -6,6 +6,7 @@ Transfer AFL files over a mesh to fuzz across multiple servers
 
 - Using DEFLATE compression format (see [RFC 1951](https://www.ietf.org/rfc/rfc1951.html))
 - Automatically syncs the main fuzzer to secondary nodes, and all secondary fuzzers back to the main node
+- Encrypts traffic between nodes using AES-256, dropping plaintext packets
 - Usable on UNIXoid (Linux, OSX) systems and Windows
 
 ## Usage
@@ -22,3 +23,17 @@ As a countermeasure, use the `--restrict-to-peers` flags to only allow connectio
 - On your host 10.0.0.2: `./afl-transmit --fuzzer-directory /ram/output --peers 10.0.0.1`
 - On your host 10.0.0.3: `./afl-transmit --fuzzer-directory /ram/output --peers 10.0.0.1`
 
+### Crypto
+
+If you want to encrypt your traffic between the nodes - which is advised, as it increases security and there is nearly no argument against it - you can do so by specifying a random key with `--key`.
+To keep *afl-transmit* simple, the symmetric encryption algorithm AES256-GCM was chosen over an asymmetric variant. This means you need to specify the same key on all nodes.
+
+Key generation is fairly simple, you just need to get 32 random bytes from somewhere (buy them, or use `/dev/urandom`), and wrap them with base64.
+For example like this:
+
+```
+dd if=/dev/urandom bs=32 count=1 2>/dev/null | base64 | tee transmit.key
+./afl-transmit --key $(cat transmit.key) --fuzzer-directory ...
+```
+
+As already said, the same key must be used on all nodes.