Update Getting-Started-with-Akka-http-signature.md

Getting-Started-with-Akka-http-signature.md

@@ -329,4 +329,62 @@ could not find actor for Actor[akka://rww/user/rootContainer/card]rww.ldp.LDPExc
         at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
         at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
 ```
+
+### Generating the .acl file
+
+It is always helpful to visualise the .acl file's relations by showing its rdf graph representation. For the file which we can build that representation looks like so: 
+
+![Pubkey.acl rdf](http://i.imgur.com/e0dOZSb.png)
+
+One can also generate this .acl file using the [banana-rdf library](https://github.com/banana-rdf/banana-rdf). This will generate an .acl in turtle format:
+
+```scala
+  val acl = WebACLPrefix[Jena]
+  val cert = CertPrefix[Jena]
+
+  val pgSeq: Seq[PointedGraph[Jena]] = Seq(
+    bnode("WriteAccess")
+      -- acl.accessTo ->- URI("https://localhost:8443/2013/pubKey")
+      -- acl.accessTo ->- URI("https://localhost:8443/2013/pubKey.ttl")
+      -- acl.agent ->- URI("https://localhost:8443/2013/pubKey#me")
+      -- acl.agent ->- (
+      bnode("agentBlankNode")
+        -- cert.key ->- URI("https://localhost:8443/2013/pubKey#")
+      )
+      -- acl.mode ->- acl.Write,
+
+    bnode("ReadAccess")
+      -- acl.agentClass ->- URI("http://xmlns.com/foaf/0.1/Agent")
+      -- acl.accessTo ->- URI("https://localhost:8443/2013/pubKey")
+      -- acl.accessTo ->- URI("https://localhost:8443/2013/pubKey.ttl")
+      -- acl.mode ->- acl.Read,
+
+    URI("")
+      -- acl.include ->- URI("https://localhost:8443/2013/.acl"),
+
+    )
+
+  val aclGraph = union(pgSeq.map(_.graph))
+  val aclttl = turtleWriter.asString(aclGraph ,"").get
+
+```
+This implementation states that the pubKey file is readable by everyone but only the person that can prove that he holds the corresponding private key has write access to it.
+
+One can then `PUT` the generated information onto the server by using the [Solid-client library](https://github.com/read-write-web/solid-client) : 
+
+```scala
+def putLocalKey = http.run(
+     req      = PUT[`text/turtle`](
+                  resource = Uri("https://localhost:8443/2013/"),
+                  graph    = aclGraph
+                ).get,
+     keyChain = List(localKey)
+   )
+```
+
+This will replace the acl file which is automatically generated by the `POST` command. 
+
+Now that the correct pubKey.acl file has been generated one can manipulate the access control of pubKey.ttl as shown above.
+
+
 ***