From dc0061c5d9756fade88c251a075dc311baf4ba29 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Thu, 3 Nov 2016 11:15:31 -0700
Subject: [PATCH 01/12] crypto box

initial utility functions for encrypted communication using crypto box
(X25519/XSalsa20-Poly1305)
---
 src/Makefile             |  2 ++
 src/utils/crypto_box.ml  | 21 +++++++++++++++++++++
 src/utils/crypto_box.mli | 20 ++++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 src/utils/crypto_box.ml
 create mode 100644 src/utils/crypto_box.mli

diff --git a/src/Makefile b/src/Makefile
index 5425b524f..7e36cde65 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -106,6 +106,7 @@ UTILS_LIB_INTFS := \
   utils/hex_encode.mli \
   utils/utils.mli \
   utils/cli_entries.mli \
+	utils/crypto_box.mli \
   utils/compare.mli \
   utils/data_encoding.mli \
   utils/time.mli \
@@ -123,6 +124,7 @@ UTILS_LIB_IMPLS := \
   utils/utils.ml \
   utils/cli_entries.ml \
   utils/compare.ml \
+	utils/crypto_box.ml \
   utils/data_encoding.ml \
   utils/time.ml \
   utils/hash.ml \
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
new file mode 100644
index 000000000..f633f851c
--- /dev/null
+++ b/src/utils/crypto_box.ml
@@ -0,0 +1,21 @@
+(**************************************************************************)
+(*                                                                        *)
+(*    Copyright (c) 2014 - 2016.                                          *)
+(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
+(*                                                                        *)
+(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
+(*                                                                        *)
+(**************************************************************************)
+
+(** Tezos - X25519/XSalsa20-Poly1305 cryptography *)
+
+type secret_key = Sodium.Box.secret_key
+type public_key = Sodium.Box.public_key
+type channel_key = Sodium.Box.channel_key
+type nonce = Sodium.Box.nonce
+
+let random_keypair = Sodium.Box.random_keypair
+let random_nonce = Sodium.Box.random_nonce
+let increment_nonce = Sodium.Box.increment_nonce
+let box = Sodium.Box.Bigbytes.box
+let box_open = Sodium.Box.Bigbytes.box_open
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
new file mode 100644
index 000000000..1df44ea44
--- /dev/null
+++ b/src/utils/crypto_box.mli
@@ -0,0 +1,20 @@
+(**************************************************************************)
+(*                                                                        *)
+(*    Copyright (c) 2014 - 2016.                                          *)
+(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
+(*                                                                        *)
+(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
+(*                                                                        *)
+(**************************************************************************)
+
+(** Tezos - X25519/XSalsa20-Poly1305 cryptography *)
+
+type secret_key
+type public_key
+type nonce
+
+val random_keypair : unit -> secret_key * public_key
+val random_nonce : unit -> nonce
+val increment_nonce : ?step:int -> nonce -> nonce
+val box : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
+val box_open : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t

From 438281f1e1dc61bdf4006f8014701c90f1887f04 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Fri, 4 Nov 2016 12:07:03 -0700
Subject: [PATCH 02/12] include a public key in peer record type

* include a public key in peer record type
* include public key in `Connect` packet
* receive/send public keys in `Connect` packet
* include public key in `connect_to_peer`
* json encode/decode public key
* include public key in peer file encode/decode
* include public key in bootstrapping
---
 src/node/net/p2p.ml      | 59 ++++++++++++++++++++++++----------------
 src/utils/crypto_box.ml  |  2 ++
 src/utils/crypto_box.mli |  2 ++
 3 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index 6ed796845..f19af5cfc 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -66,7 +66,7 @@ type point = addr * port
    not a real kind of packet, it means that something indecypherable
    was transmitted. *)
 type packet =
-  | Connect of gid * int option * version list
+  | Connect of gid * Crypto_box.public_key * int option * version list
   | Disconnect
   | Advertise of (addr * port) list
   | Message of Netbits.frame
@@ -96,12 +96,12 @@ let recv_packet
         | [ S 2 ] -> return Ping
         | [ S 12 ] -> return Pong
         | [ S 3 ] -> return Bootstrap
-        | [ S 4 ; B gid ; S port ; F rest ] as msg ->
+        | [ S 4 ; B gid ; B public_key ; S port ; F rest ] as msg ->
             decode_versions msg rest @@ fun versions ->
-            return (Connect (MBytes.to_string gid, Some port, versions))
-        | [ S 4 ; B gid ; F rest ] as msg ->
+            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, Some port, versions))
+        | [ S 4 ; B gid ; B public_key ; F rest ] as msg ->
             decode_versions msg rest @@ fun versions ->
-            return (Connect (MBytes.to_string gid, None, versions))
+            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, None, versions))
         | [ S 5 ; F rest ] as msg ->
             let rec decode_peers acc = function
               | F [ B addr ; S port ] :: rest -> begin
@@ -127,14 +127,14 @@ let send_packet
       | Ping -> [ S 2 ]
       | Pong -> [ S 12 ]
       | Bootstrap -> [ S 3 ]
-      | Connect (gid, port, versions) ->
+      | Connect (gid, public_key, port, versions) ->
           let rec encode = function
             | (name, maj, min) :: tl ->
                 let rest = encode tl in
                 F [ B (MBytes.of_string name) ; S maj ; S min ] :: rest
             | [] -> []
           in
-          [ S 4 ; B (MBytes.of_string gid) ]
+          [ S 4 ; B (MBytes.of_string gid) ; B (Crypto_box.of_public_key public_key) ]
           @ (match port with | Some port -> [ S port ] | None -> [])
           @ [ F (encode versions) ]
       | Advertise peers ->
@@ -170,6 +170,7 @@ type net = {
    workers (on shutdown of during maintenance). *)
 and peer = {
   gid : gid ;
+  public_key : Crypto_box.public_key ;
   point : point ;
   listening_port : port option ;
   version : version ;
@@ -282,7 +283,7 @@ end
    function for communicating with the main worker using events
    (including the one sent when the connection is alive). Returns a
    canceler. *)
-let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
+let connect_to_peer config limits my_gid my_public_key socket (addr, port) push white_listed =
   (* a non exception-based cancelation mechanism *)
   let cancelation, cancel, on_cancel = canceler () in
   (* a cancelable reception *)
@@ -294,11 +295,12 @@ let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
      connection, both parties must first present themselves. *)
   let rec connect () =
     send_packet socket (Connect (my_gid,
+                                 my_public_key,
                                  config.incoming_port,
                                  config.supported_versions)) >>= fun _ ->
     pick [ (LU.sleep limits.peer_answer_timeout >>= fun () -> return Disconnect) ;
            recv () ] >>= function
-    | Connect (gid, listening_port, versions) ->
+    | Connect (gid, public_key , listening_port, versions) ->
         debug "(%a) connection requested from %a @ %a:%d"
           pp_gid my_gid pp_gid gid Ipaddr.pp_hum addr port ;
         begin match common_version config.supported_versions versions with
@@ -310,7 +312,7 @@ let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
               if config.closed_network then
                 match listening_port with
                 | Some port when white_listed (addr, port) ->
-                    connected version gid listening_port
+                    connected version gid public_key listening_port
                 | Some port ->
                     debug "(%a) connection rejected (out of the closed network) from %a:%d"
                       pp_gid my_gid Ipaddr.pp_hum addr port ;
@@ -320,7 +322,7 @@ let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
                       pp_gid my_gid Ipaddr.pp_hum addr ;
                     cancel ()
               else
-                connected version gid listening_port
+                connected version gid public_key listening_port
         end
     | Advertise peers ->
         (* alternatively, one can refuse a connection but reply with
@@ -338,7 +340,7 @@ let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
           pp_gid my_gid Ipaddr.pp_hum addr port ;
         cancel ()
   (* Them we can build the net object and launch the worker. *)
-  and connected version gid listening_port =
+  and connected version gid public_key listening_port =
     (* net object state *)
     let last = ref (Unix.gettimeofday ()) in
     (* net object callbaks *)
@@ -346,7 +348,7 @@ let connect_to_peer config limits my_gid socket (addr, port) push white_listed =
     let disconnect () = cancel () in
     let send p = send_packet socket p >>= fun _ -> return () in
     (* net object construction *)
-    let peer = { gid ; point = (addr, port) ; listening_port ;
+    let peer = { gid ; public_key ; point = (addr, port) ; listening_port ;
                  version ; last_seen ; disconnect ; send } in
     (* The packet reception loop. *)
     let rec receiver () =
@@ -429,10 +431,18 @@ let addr_encoding =
              (fun b -> Ipaddr.(V6 (V6.of_bytes_exn b))) ;
          ])
 
+let public_key_encoding =
+  let open Data_encoding in
+    conv
+      (fun public_key -> MBytes.to_string (Crypto_box.of_public_key public_key))
+      (fun str -> Crypto_box.to_public_key (MBytes.of_string str))
+      string
+
 let peers_file_encoding =
   let open Data_encoding in
-  obj2
+  obj3
     (req "gid" string)
+    (req "public_key" public_key_encoding)
     (req "peers"
        (obj3
           (req "known"
@@ -591,10 +601,12 @@ let bootstrap config limits =
   on_cancel (fun () -> close_msg_queue () ; return ()) ;
   (* fill the known peers pools from last time *)
   Data_encoding.Json.read_file config.peers_file >>= fun res ->
-  let known_peers, black_list, my_gid =
+  let known_peers, black_list, my_gid, my_public_key =
     let init_peers () =
       let my_gid =
         fresh_gid () in
+      let (my_secret_key, my_public_key) =
+        Crypto_box.random_keypair () in
       let known_peers =
         let source =
           { unreachable_since = None ;
@@ -605,19 +617,19 @@ let bootstrap config limits =
           PeerMap.empty config.known_peers in
       let black_list =
         BlackList.empty in
-      known_peers, black_list, my_gid in
+      known_peers, black_list, my_gid, my_public_key in
     match res with
     | None ->
-        let known_peers, black_list, my_gid = init_peers () in
+        let known_peers, black_list, my_gid, my_public_key = init_peers () in
         debug "(%a) peer cache initiated" pp_gid my_gid ;
-        ref known_peers, ref black_list, my_gid
+        ref known_peers, ref black_list, my_gid, my_public_key
     | Some json ->
         match Data_encoding.Json.destruct peers_file_encoding json with
         | exception _ ->
-            let known_peers, black_list, my_gid = init_peers () in
+            let known_peers, black_list, my_gid, my_public_key = init_peers () in
             debug "(%a) peer cache reset" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid
-        | (my_gid, (k, b, w)) ->
+            ref known_peers, ref black_list, my_gid, my_public_key
+        | (my_gid, my_public_key, (k, b, w)) ->
             let white_list =
               List.fold_right PointSet.add w PointSet.empty in
             let known_peers =
@@ -642,7 +654,7 @@ let bootstrap config limits =
                 (fun r (a, d) -> BlackList.add a d r)
                 BlackList.empty b in
             debug "(%a) peer cache loaded" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid
+            ref known_peers, ref black_list, my_gid, my_public_key
   in
   (* some peer reachability predicates *)
   let black_listed (addr, _) =
@@ -660,6 +672,7 @@ let bootstrap config limits =
       let json =
         Data_encoding.Json.construct peers_file_encoding @@
         (my_gid,
+         my_public_key,
          PeerMap.fold
            (fun (addr, port) gid source (k, b, w) ->
               let infos = match gid, source.connections with
@@ -919,7 +932,7 @@ let bootstrap config limits =
           main ()
         else
           let canceler =
-            connect_to_peer config limits my_gid socket (addr, port) enqueue_event white_listed in
+            connect_to_peer config limits my_gid my_public_key socket (addr, port) enqueue_event white_listed in
           debug "(%a) incoming peer at %a:%d"
             pp_gid my_gid Ipaddr.pp_hum addr port ;
           incoming := PointMap.add (addr, port) canceler !incoming ;
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index f633f851c..d53fa84ec 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -19,3 +19,5 @@ let random_nonce = Sodium.Box.random_nonce
 let increment_nonce = Sodium.Box.increment_nonce
 let box = Sodium.Box.Bigbytes.box
 let box_open = Sodium.Box.Bigbytes.box_open
+let to_public_key = Sodium.Box.Bigbytes.to_public_key
+let of_public_key = Sodium.Box.Bigbytes.of_public_key
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
index 1df44ea44..9e1243ad7 100644
--- a/src/utils/crypto_box.mli
+++ b/src/utils/crypto_box.mli
@@ -18,3 +18,5 @@ val random_nonce : unit -> nonce
 val increment_nonce : ?step:int -> nonce -> nonce
 val box : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
 val box_open : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
+val to_public_key : MBytes.t -> public_key
+val of_public_key : public_key -> MBytes.t

From b8b93651af0745be5aad4261ba47ebb7f66a831d Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Fri, 4 Nov 2016 12:22:22 -0700
Subject: [PATCH 03/12] composition operator

added composition operator to utils module
---
 src/node/net/p2p.ml | 4 ++--
 src/utils/utils.ml  | 2 ++
 src/utils/utils.mli | 2 ++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index f19af5cfc..9bf11f423 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -434,8 +434,8 @@ let addr_encoding =
 let public_key_encoding =
   let open Data_encoding in
     conv
-      (fun public_key -> MBytes.to_string (Crypto_box.of_public_key public_key))
-      (fun str -> Crypto_box.to_public_key (MBytes.of_string str))
+      (MBytes.to_string << Crypto_box.of_public_key)
+      (Crypto_box.to_public_key << MBytes.of_string)
       string
 
 let peers_file_encoding =
diff --git a/src/utils/utils.ml b/src/utils/utils.ml
index ef2fe1f48..97969003d 100644
--- a/src/utils/utils.ml
+++ b/src/utils/utils.ml
@@ -121,3 +121,5 @@ let rec remove_elem_from_list nb = function
   | [] -> []
   | l when nb <= 0 -> l
   | _ :: tl -> remove_elem_from_list (nb - 1) tl
+
+let (<<) g f = fun a -> g (f a)
diff --git a/src/utils/utils.mli b/src/utils/utils.mli
index a027b783f..f2abbdf92 100644
--- a/src/utils/utils.mli
+++ b/src/utils/utils.mli
@@ -38,3 +38,5 @@ val remove_elem_from_list: int -> 'a list -> 'a list
 
 val filter_map: ('a -> 'b option) -> 'a list -> 'b list
 
+(** Compose functions from right to left. *)
+val (<<) : ('b -> 'c) -> ('a -> 'b) -> 'a -> 'c

From 3a5368434c22c7f7ceff565f114642f9d74c8929 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Sat, 5 Nov 2016 09:12:25 -0700
Subject: [PATCH 04/12] add secret key to peer file

---
 src/node/net/p2p.ml      | 27 ++++++++++++++++++---------
 src/utils/crypto_box.ml  |  2 ++
 src/utils/crypto_box.mli |  2 ++
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index 9bf11f423..bf88a2703 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -438,11 +438,19 @@ let public_key_encoding =
       (Crypto_box.to_public_key << MBytes.of_string)
       string
 
+let secret_key_encoding =
+  let open Data_encoding in
+    conv
+      (MBytes.to_string << Crypto_box.of_secret_key)
+      (Crypto_box.to_secret_key << MBytes.of_string)
+      string
+
 let peers_file_encoding =
   let open Data_encoding in
-  obj3
+  obj4
     (req "gid" string)
     (req "public_key" public_key_encoding)
+    (req "secret_key" secret_key_encoding)
     (req "peers"
        (obj3
           (req "known"
@@ -601,7 +609,7 @@ let bootstrap config limits =
   on_cancel (fun () -> close_msg_queue () ; return ()) ;
   (* fill the known peers pools from last time *)
   Data_encoding.Json.read_file config.peers_file >>= fun res ->
-  let known_peers, black_list, my_gid, my_public_key =
+  let known_peers, black_list, my_gid, my_public_key, my_secret_key =
     let init_peers () =
       let my_gid =
         fresh_gid () in
@@ -617,19 +625,19 @@ let bootstrap config limits =
           PeerMap.empty config.known_peers in
       let black_list =
         BlackList.empty in
-      known_peers, black_list, my_gid, my_public_key in
+      known_peers, black_list, my_gid, my_public_key, my_secret_key in
     match res with
     | None ->
-        let known_peers, black_list, my_gid, my_public_key = init_peers () in
+        let known_peers, black_list, my_gid, my_public_key, my_secret_key = init_peers () in
         debug "(%a) peer cache initiated" pp_gid my_gid ;
-        ref known_peers, ref black_list, my_gid, my_public_key
+        ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
     | Some json ->
         match Data_encoding.Json.destruct peers_file_encoding json with
         | exception _ ->
-            let known_peers, black_list, my_gid, my_public_key = init_peers () in
+            let known_peers, black_list, my_gid, my_public_key, my_secret_key = init_peers () in
             debug "(%a) peer cache reset" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid, my_public_key
-        | (my_gid, my_public_key, (k, b, w)) ->
+            ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
+        | (my_gid, my_public_key, my_secret_key, (k, b, w)) ->
             let white_list =
               List.fold_right PointSet.add w PointSet.empty in
             let known_peers =
@@ -654,7 +662,7 @@ let bootstrap config limits =
                 (fun r (a, d) -> BlackList.add a d r)
                 BlackList.empty b in
             debug "(%a) peer cache loaded" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid, my_public_key
+            ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
   in
   (* some peer reachability predicates *)
   let black_listed (addr, _) =
@@ -673,6 +681,7 @@ let bootstrap config limits =
         Data_encoding.Json.construct peers_file_encoding @@
         (my_gid,
          my_public_key,
+         my_secret_key,
          PeerMap.fold
            (fun (addr, port) gid source (k, b, w) ->
               let infos = match gid, source.connections with
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index d53fa84ec..e9ea2f904 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -19,5 +19,7 @@ let random_nonce = Sodium.Box.random_nonce
 let increment_nonce = Sodium.Box.increment_nonce
 let box = Sodium.Box.Bigbytes.box
 let box_open = Sodium.Box.Bigbytes.box_open
+let to_secret_key = Sodium.Box.Bigbytes.to_secret_key
+let of_secret_key = Sodium.Box.Bigbytes.of_secret_key
 let to_public_key = Sodium.Box.Bigbytes.to_public_key
 let of_public_key = Sodium.Box.Bigbytes.of_public_key
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
index 9e1243ad7..1908e18b3 100644
--- a/src/utils/crypto_box.mli
+++ b/src/utils/crypto_box.mli
@@ -18,5 +18,7 @@ val random_nonce : unit -> nonce
 val increment_nonce : ?step:int -> nonce -> nonce
 val box : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
 val box_open : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
+val to_secret_key : MBytes.t -> secret_key
+val of_secret_key : secret_key -> MBytes.t
 val to_public_key : MBytes.t -> public_key
 val of_public_key : public_key -> MBytes.t

From bdab9b6c0586046b41f308d893bc1d5d1fc8d89b Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Sat, 5 Nov 2016 09:32:32 -0700
Subject: [PATCH 05/12] peer public keys

add peer public keys to known peers in peers file
---
 src/node/net/p2p.ml | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index bf88a2703..3a4057110 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -458,10 +458,11 @@ let peers_file_encoding =
                        (req "addr" addr_encoding)
                        (req "port" int31)
                        (opt "infos"
-                          (obj3
+                          (obj4
                              (req "connections" int31)
                              (req "lastSeen" float)
-                             (req "gid" string))))))
+                             (req "gid" string)
+                             (req "public_key" public_key_encoding))))))
           (req "blacklisted"
              (list (obj2
                        (req "addr" addr_encoding)
@@ -474,7 +475,7 @@ let peers_file_encoding =
 (* Info on peers maintained between connections *)
 type source =
   { unreachable_since : float option;
-    connections : (int * float) option ;
+    connections : (int * float * Crypto_box.public_key) option ;
     white_listed : bool }
 
 (* Ad hoc comparison on sources such as good source < bad source *)
@@ -487,7 +488,7 @@ let compare_sources s1 s2 =
       | _, _ ->
           match s1.connections, s2.connections with
           | Some _, None -> -1 | None, Some _ -> 1 | None, None -> 0
-          | Some (n1, t1), Some (n2, t2) ->
+          | Some (n1, t1, _), Some (n2, t2, _) ->
               if n1 = n2 then compare t2 t1
               else compare n2 n1
 
@@ -650,10 +651,10 @@ let bootstrap config limits =
                            connections = None ;
                            white_listed = true } in
                        PeerMap.update (addr, port) source r
-                   | Some (c, t, gid) ->
+                   | Some (c, t, gid, pk) ->
                        let source =
                          { unreachable_since = None ;
-                           connections = Some (c, t) ;
+                           connections = Some (c, t, pk) ;
                            white_listed = PointSet.mem (addr, port) white_list } in
                        PeerMap.update (addr, port) ~gid source r)
                 PeerMap.empty k in
@@ -685,7 +686,7 @@ let bootstrap config limits =
          PeerMap.fold
            (fun (addr, port) gid source (k, b, w) ->
               let infos = match gid, source.connections with
-                | Some gid, Some (n, t) -> Some (n, t, gid)
+                | Some gid, Some (n, t, pk) -> Some (n, t, gid, pk)
                 | _ -> None in
               ((addr, port, infos) :: k,
                b,
@@ -891,15 +892,15 @@ let bootstrap config limits =
               in update @@
               try match PeerMap.by_gid peer.gid !known_peers with
                 | { connections = None ; white_listed } ->
-                    { connections = Some (1, Unix.gettimeofday ()) ;
+                    { connections = Some (1, Unix.gettimeofday (), peer.public_key) ;
                       unreachable_since = None ;
                       white_listed }
-                | { connections = Some (n, _) ; white_listed } ->
-                    { connections = Some (n + 1, Unix.gettimeofday ()) ;
+                | { connections = Some (n, _, _) ; white_listed } ->
+                    { connections = Some (n + 1, Unix.gettimeofday (), peer.public_key) ;
                       unreachable_since = None ;
                       white_listed}
               with Not_found ->
-                { connections = Some (1, Unix.gettimeofday ()) ;
+                { connections = Some (1, Unix.gettimeofday (), peer.public_key) ;
                   unreachable_since = None ;
                   white_listed = white_listed point }
         in

From 69bc2a33e2cecf679dfcbb1fffa967f3118e1ddd Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Sat, 5 Nov 2016 12:16:48 -0700
Subject: [PATCH 06/12] encryption and decryption
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

I don’t think this is secure since the receiver decrypts the message
and then sends the clear message as a `Recv` event
---
 src/node/net/p2p.ml      | 20 ++++++++++++++++----
 src/utils/crypto_box.ml  |  2 ++
 src/utils/crypto_box.mli |  2 ++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index 3a4057110..4b5a27c09 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -70,6 +70,7 @@ type packet =
   | Disconnect
   | Advertise of (addr * port) list
   | Message of Netbits.frame
+  | Box of (Crypto_box.nonce * MBytes.t)
   | Ping
   | Pong
   | Bootstrap
@@ -115,6 +116,7 @@ let recv_packet
               | _ -> Unknown msg
             in return (decode_peers [] rest)
         | [ S 6 ; F rest ] -> return (Message rest)
+        | [ S 7 ; B nonce ; B msg ] -> return (Box (Crypto_box.to_nonce nonce, msg))
         | msg -> return (Unknown msg)
 
 (* send a packet over a TCP socket *)
@@ -144,7 +146,8 @@ let send_packet
                 F [ B (MBytes.of_string @@ Ipaddr.to_string addr) ; S port ] :: rest
             | [] -> []
           in [ S 5 ; F (encode peers) ]
-      | Message message -> [ S 6 ; F message ] in
+      | Message message -> [ S 6 ; F message ]
+      | Box (nonce , message) -> [ S 7 ; B (Crypto_box.of_nonce nonce) ; B message ] in
     Netbits.write socket frame
 
 (* A net handler, as a record-encoded object, abstract from the
@@ -177,6 +180,7 @@ and peer = {
   last_seen : unit -> float ;
   disconnect : unit -> unit Lwt.t;
   send : packet -> unit Lwt.t ;
+  send_encr : MBytes.t -> unit Lwt.t ;
 }
 
 (* The (internal) type of network events, those dispatched from peer
@@ -283,7 +287,7 @@ end
    function for communicating with the main worker using events
    (including the one sent when the connection is alive). Returns a
    canceler. *)
-let connect_to_peer config limits my_gid my_public_key socket (addr, port) push white_listed =
+let connect_to_peer config limits my_gid my_public_key my_secret_key socket (addr, port) push white_listed =
   (* a non exception-based cancelation mechanism *)
   let cancelation, cancel, on_cancel = canceler () in
   (* a cancelable reception *)
@@ -347,9 +351,14 @@ let connect_to_peer config limits my_gid my_public_key socket (addr, port) push
     let last_seen () = !last in
     let disconnect () = cancel () in
     let send p = send_packet socket p >>= fun _ -> return () in
+    let send_encr msg =
+      let nonce = Crypto_box.random_nonce () in
+      let msg_encr = Crypto_box.box my_secret_key public_key msg nonce in
+      let packet = Box (nonce, msg_encr) in
+      send_packet socket packet >>= fun _ -> return () in
     (* net object construction *)
     let peer = { gid ; public_key ; point = (addr, port) ; listening_port ;
-                 version ; last_seen ; disconnect ; send } in
+                 version ; last_seen ; disconnect ; send ; send_encr } in
     (* The packet reception loop. *)
     let rec receiver () =
       recv () >>= fun packet ->
@@ -370,6 +379,9 @@ let connect_to_peer config limits my_gid my_public_key socket (addr, port) push
       | Pong -> receiver ()
       | Message msg ->
           push (Recv (peer, msg)) ; receiver ()
+      | Box (nonce, msg_encr) ->
+          let msg = Crypto_box.box_open my_secret_key public_key msg_encr nonce in
+          push (Recv (peer, [B msg])) ; receiver ()
     in
     (* The polling loop *)
     let rec pulse_monitor ping =
@@ -942,7 +954,7 @@ let bootstrap config limits =
           main ()
         else
           let canceler =
-            connect_to_peer config limits my_gid my_public_key socket (addr, port) enqueue_event white_listed in
+            connect_to_peer config limits my_gid my_public_key my_secret_key socket (addr, port) enqueue_event white_listed in
           debug "(%a) incoming peer at %a:%d"
             pp_gid my_gid Ipaddr.pp_hum addr port ;
           incoming := PointMap.add (addr, port) canceler !incoming ;
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index e9ea2f904..cdef24b97 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -23,3 +23,5 @@ let to_secret_key = Sodium.Box.Bigbytes.to_secret_key
 let of_secret_key = Sodium.Box.Bigbytes.of_secret_key
 let to_public_key = Sodium.Box.Bigbytes.to_public_key
 let of_public_key = Sodium.Box.Bigbytes.of_public_key
+let to_nonce = Sodium.Box.Bigbytes.to_nonce
+let of_nonce = Sodium.Box.Bigbytes.of_nonce
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
index 1908e18b3..d870b0bb2 100644
--- a/src/utils/crypto_box.mli
+++ b/src/utils/crypto_box.mli
@@ -22,3 +22,5 @@ val to_secret_key : MBytes.t -> secret_key
 val of_secret_key : secret_key -> MBytes.t
 val to_public_key : MBytes.t -> public_key
 val of_public_key : public_key -> MBytes.t
+val to_nonce : MBytes.t -> nonce
+val of_nonce : nonce -> MBytes.t

From b3efe1ad0ad261bfd226d58c1c7256de2baea8ca Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Sat, 5 Nov 2016 14:32:13 -0700
Subject: [PATCH 07/12] testing code

---
 src/node/net/p2p.ml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index 4b5a27c09..e59274a78 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -355,6 +355,7 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
       let nonce = Crypto_box.random_nonce () in
       let msg_encr = Crypto_box.box my_secret_key public_key msg nonce in
       let packet = Box (nonce, msg_encr) in
+      Format.printf "encoding %s as %s" (MBytes.to_string msg) (MBytes.to_string msg_encr);
       send_packet socket packet >>= fun _ -> return () in
     (* net object construction *)
     let peer = { gid ; public_key ; point = (addr, port) ; listening_port ;
@@ -381,6 +382,7 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
           push (Recv (peer, msg)) ; receiver ()
       | Box (nonce, msg_encr) ->
           let msg = Crypto_box.box_open my_secret_key public_key msg_encr nonce in
+          Format.printf "decoding %s as %s" (MBytes.to_string msg_encr) (MBytes.to_string msg);
           push (Recv (peer, [B msg])) ; receiver ()
     in
     (* The polling loop *)
@@ -1069,7 +1071,8 @@ let bootstrap config limits =
   and recv_from () =
     dequeue_msg ()
   and send_to (peer, msg) =
-    peer.send (Message msg) >>= fun _ -> return ()
+    peer.send (Message msg) <&>
+    peer.send_encr (MBytes.of_string "Eitan")
   and push (peer, msg) =
     Lwt.async (fun () -> peer.send (Message msg))
   and broadcast msg =

From 001ba994a8124a812fa54f004fc99cbcc91671ed Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Mon, 7 Nov 2016 11:30:13 -0800
Subject: [PATCH 08/12] negotiate nonce during peer connection

---
 src/node/net/p2p.ml | 74 ++++++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 35 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index e59274a78..c479fe683 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -66,11 +66,11 @@ type point = addr * port
    not a real kind of packet, it means that something indecypherable
    was transmitted. *)
 type packet =
-  | Connect of gid * Crypto_box.public_key * int option * version list
+  | Connect of gid * Crypto_box.public_key * Crypto_box.nonce * int option * version list
   | Disconnect
   | Advertise of (addr * port) list
   | Message of Netbits.frame
-  | Box of (Crypto_box.nonce * MBytes.t)
+  | Box of MBytes.t
   | Ping
   | Pong
   | Bootstrap
@@ -97,12 +97,12 @@ let recv_packet
         | [ S 2 ] -> return Ping
         | [ S 12 ] -> return Pong
         | [ S 3 ] -> return Bootstrap
-        | [ S 4 ; B gid ; B public_key ; S port ; F rest ] as msg ->
+        | [ S 4 ; B gid ; B public_key ; B nonce ; S port ; F rest ] as msg ->
             decode_versions msg rest @@ fun versions ->
-            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, Some port, versions))
-        | [ S 4 ; B gid ; B public_key ; F rest ] as msg ->
+            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, Crypto_box.to_nonce nonce, Some port, versions))
+        | [ S 4 ; B gid ; B public_key ; B nonce ; F rest ] as msg ->
             decode_versions msg rest @@ fun versions ->
-            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, None, versions))
+            return (Connect (MBytes.to_string gid, Crypto_box.to_public_key public_key, Crypto_box.to_nonce nonce, None, versions))
         | [ S 5 ; F rest ] as msg ->
             let rec decode_peers acc = function
               | F [ B addr ; S port ] :: rest -> begin
@@ -116,7 +116,7 @@ let recv_packet
               | _ -> Unknown msg
             in return (decode_peers [] rest)
         | [ S 6 ; F rest ] -> return (Message rest)
-        | [ S 7 ; B nonce ; B msg ] -> return (Box (Crypto_box.to_nonce nonce, msg))
+        | [ S 7 ; B msg ] -> return (Box msg)
         | msg -> return (Unknown msg)
 
 (* send a packet over a TCP socket *)
@@ -129,14 +129,14 @@ let send_packet
       | Ping -> [ S 2 ]
       | Pong -> [ S 12 ]
       | Bootstrap -> [ S 3 ]
-      | Connect (gid, public_key, port, versions) ->
+      | Connect (gid, public_key, nonce, port, versions) ->
           let rec encode = function
             | (name, maj, min) :: tl ->
                 let rest = encode tl in
                 F [ B (MBytes.of_string name) ; S maj ; S min ] :: rest
             | [] -> []
           in
-          [ S 4 ; B (MBytes.of_string gid) ; B (Crypto_box.of_public_key public_key) ]
+          [ S 4 ; B (MBytes.of_string gid) ; B (Crypto_box.of_public_key public_key) ; B (Crypto_box.of_nonce nonce) ]
           @ (match port with | Some port -> [ S port ] | None -> [])
           @ [ F (encode versions) ]
       | Advertise peers ->
@@ -147,7 +147,7 @@ let send_packet
             | [] -> []
           in [ S 5 ; F (encode peers) ]
       | Message message -> [ S 6 ; F message ]
-      | Box (nonce , message) -> [ S 7 ; B (Crypto_box.of_nonce nonce) ; B message ] in
+      | Box message -> [ S 7 ; B message ] in
     Netbits.write socket frame
 
 (* A net handler, as a record-encoded object, abstract from the
@@ -174,6 +174,7 @@ type net = {
 and peer = {
   gid : gid ;
   public_key : Crypto_box.public_key ;
+  current_nonce : unit -> Crypto_box.nonce ;
   point : point ;
   listening_port : port option ;
   version : version ;
@@ -287,7 +288,7 @@ end
    function for communicating with the main worker using events
    (including the one sent when the connection is alive). Returns a
    canceler. *)
-let connect_to_peer config limits my_gid my_public_key my_secret_key socket (addr, port) push white_listed =
+let connect_to_peer config limits my_gid my_public_key my_nonce my_secret_key socket (addr, port) push white_listed =
   (* a non exception-based cancelation mechanism *)
   let cancelation, cancel, on_cancel = canceler () in
   (* a cancelable reception *)
@@ -300,11 +301,12 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
   let rec connect () =
     send_packet socket (Connect (my_gid,
                                  my_public_key,
+                                 my_nonce,
                                  config.incoming_port,
                                  config.supported_versions)) >>= fun _ ->
     pick [ (LU.sleep limits.peer_answer_timeout >>= fun () -> return Disconnect) ;
            recv () ] >>= function
-    | Connect (gid, public_key , listening_port, versions) ->
+    | Connect (gid, public_key , nonce, listening_port, versions) ->
         debug "(%a) connection requested from %a @ %a:%d"
           pp_gid my_gid pp_gid gid Ipaddr.pp_hum addr port ;
         begin match common_version config.supported_versions versions with
@@ -316,7 +318,7 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
               if config.closed_network then
                 match listening_port with
                 | Some port when white_listed (addr, port) ->
-                    connected version gid public_key listening_port
+                    connected version gid public_key nonce listening_port
                 | Some port ->
                     debug "(%a) connection rejected (out of the closed network) from %a:%d"
                       pp_gid my_gid Ipaddr.pp_hum addr port ;
@@ -326,7 +328,7 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
                       pp_gid my_gid Ipaddr.pp_hum addr ;
                     cancel ()
               else
-                connected version gid public_key listening_port
+                connected version gid public_key nonce listening_port
         end
     | Advertise peers ->
         (* alternatively, one can refuse a connection but reply with
@@ -344,21 +346,22 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
           pp_gid my_gid Ipaddr.pp_hum addr port ;
         cancel ()
   (* Them we can build the net object and launch the worker. *)
-  and connected version gid public_key listening_port =
+  and connected version gid public_key nonce listening_port =
     (* net object state *)
     let last = ref (Unix.gettimeofday ()) in
+    let the_nonce = ref nonce in
     (* net object callbaks *)
     let last_seen () = !last in
+    let current_nonce () = !the_nonce in
+    let next_nonce () = the_nonce := Crypto_box.increment_nonce !the_nonce in
     let disconnect () = cancel () in
     let send p = send_packet socket p >>= fun _ -> return () in
     let send_encr msg =
-      let nonce = Crypto_box.random_nonce () in
-      let msg_encr = Crypto_box.box my_secret_key public_key msg nonce in
-      let packet = Box (nonce, msg_encr) in
-      Format.printf "encoding %s as %s" (MBytes.to_string msg) (MBytes.to_string msg_encr);
-      send_packet socket packet >>= fun _ -> return () in
+      let msg_encr = Crypto_box.box my_secret_key public_key msg (current_nonce ()) in
+      let packet = Box msg_encr in
+      next_nonce (); send_packet socket packet >>= fun _ -> return () in
     (* net object construction *)
-    let peer = { gid ; public_key ; point = (addr, port) ; listening_port ;
+    let peer = { gid ; public_key ; current_nonce ; point = (addr, port) ; listening_port ;
                  version ; last_seen ; disconnect ; send ; send_encr } in
     (* The packet reception loop. *)
     let rec receiver () =
@@ -380,9 +383,8 @@ let connect_to_peer config limits my_gid my_public_key my_secret_key socket (add
       | Pong -> receiver ()
       | Message msg ->
           push (Recv (peer, msg)) ; receiver ()
-      | Box (nonce, msg_encr) ->
-          let msg = Crypto_box.box_open my_secret_key public_key msg_encr nonce in
-          Format.printf "decoding %s as %s" (MBytes.to_string msg_encr) (MBytes.to_string msg);
+      | Box msg_encr ->
+          let msg = Crypto_box.box_open my_secret_key public_key msg_encr (peer.current_nonce ()) in
           push (Recv (peer, [B msg])) ; receiver ()
     in
     (* The polling loop *)
@@ -624,12 +626,14 @@ let bootstrap config limits =
   on_cancel (fun () -> close_msg_queue () ; return ()) ;
   (* fill the known peers pools from last time *)
   Data_encoding.Json.read_file config.peers_file >>= fun res ->
-  let known_peers, black_list, my_gid, my_public_key, my_secret_key =
+  let known_peers, black_list, my_gid, my_public_key, my_nonce, my_secret_key =
     let init_peers () =
       let my_gid =
         fresh_gid () in
       let (my_secret_key, my_public_key) =
         Crypto_box.random_keypair () in
+      let my_nonce =
+        Crypto_box.random_nonce () in
       let known_peers =
         let source =
           { unreachable_since = None ;
@@ -640,18 +644,18 @@ let bootstrap config limits =
           PeerMap.empty config.known_peers in
       let black_list =
         BlackList.empty in
-      known_peers, black_list, my_gid, my_public_key, my_secret_key in
+      known_peers, black_list, my_gid, my_public_key, my_nonce, my_secret_key in
     match res with
     | None ->
-        let known_peers, black_list, my_gid, my_public_key, my_secret_key = init_peers () in
+        let known_peers, black_list, my_gid, my_public_key, my_nonce, my_secret_key = init_peers () in
         debug "(%a) peer cache initiated" pp_gid my_gid ;
-        ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
+        ref known_peers, ref black_list, my_gid, my_public_key, my_nonce, my_secret_key
     | Some json ->
         match Data_encoding.Json.destruct peers_file_encoding json with
         | exception _ ->
-            let known_peers, black_list, my_gid, my_public_key, my_secret_key = init_peers () in
+            let known_peers, black_list, my_gid, my_public_key, my_nonce, my_secret_key = init_peers () in
             debug "(%a) peer cache reset" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
+            ref known_peers, ref black_list, my_gid, my_public_key, my_nonce, my_secret_key
         | (my_gid, my_public_key, my_secret_key, (k, b, w)) ->
             let white_list =
               List.fold_right PointSet.add w PointSet.empty in
@@ -676,8 +680,10 @@ let bootstrap config limits =
               List.fold_left
                 (fun r (a, d) -> BlackList.add a d r)
                 BlackList.empty b in
+            let my_nonce =
+              Crypto_box.random_nonce () in
             debug "(%a) peer cache loaded" pp_gid my_gid ;
-            ref known_peers, ref black_list, my_gid, my_public_key, my_secret_key
+            ref known_peers, ref black_list, my_gid, my_public_key, my_nonce, my_secret_key
   in
   (* some peer reachability predicates *)
   let black_listed (addr, _) =
@@ -956,7 +962,7 @@ let bootstrap config limits =
           main ()
         else
           let canceler =
-            connect_to_peer config limits my_gid my_public_key my_secret_key socket (addr, port) enqueue_event white_listed in
+            connect_to_peer config limits my_gid my_public_key my_nonce my_secret_key socket (addr, port) enqueue_event white_listed in
           debug "(%a) incoming peer at %a:%d"
             pp_gid my_gid Ipaddr.pp_hum addr port ;
           incoming := PointMap.add (addr, port) canceler !incoming ;
@@ -1070,9 +1076,7 @@ let bootstrap config limits =
     fst peer.point, snd peer.point, peer.version
   and recv_from () =
     dequeue_msg ()
-  and send_to (peer, msg) =
-    peer.send (Message msg) <&>
-    peer.send_encr (MBytes.of_string "Eitan")
+  and send_to (peer, msg) = peer.send (Message msg)
   and push (peer, msg) =
     Lwt.async (fun () -> peer.send (Message msg))
   and broadcast msg =

From 1733cd499a6396b84d77bca6885a55af8ffb5906 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Mon, 7 Nov 2016 14:38:02 -0800
Subject: [PATCH 09/12] handle decryption exceptions

---
 src/node/net/p2p.ml      | 7 +++++--
 src/utils/crypto_box.ml  | 4 +++-
 src/utils/crypto_box.mli | 2 +-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index c479fe683..e6e97f961 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -384,8 +384,11 @@ let connect_to_peer config limits my_gid my_public_key my_nonce my_secret_key so
       | Message msg ->
           push (Recv (peer, msg)) ; receiver ()
       | Box msg_encr ->
-          let msg = Crypto_box.box_open my_secret_key public_key msg_encr (peer.current_nonce ()) in
-          push (Recv (peer, [B msg])) ; receiver ()
+          Crypto_box.box_open my_secret_key public_key msg_encr (peer.current_nonce ())
+            |> function
+              | None -> debug "(%a) cannot decrypt message (from peer) %a @ %a:%d"
+                  pp_gid my_gid pp_gid gid Ipaddr.pp_hum addr port ; receiver ()
+              | Some msg -> push (Recv (peer, [B msg])) ; receiver ()
     in
     (* The polling loop *)
     let rec pulse_monitor ping =
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index cdef24b97..8931436c9 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -18,7 +18,9 @@ let random_keypair = Sodium.Box.random_keypair
 let random_nonce = Sodium.Box.random_nonce
 let increment_nonce = Sodium.Box.increment_nonce
 let box = Sodium.Box.Bigbytes.box
-let box_open = Sodium.Box.Bigbytes.box_open
+let box_open sk pk msg nonce =
+  try Some (Sodium.Box.Bigbytes.box_open sk pk msg nonce) with
+    | Sodium.Verification_failure -> None
 let to_secret_key = Sodium.Box.Bigbytes.to_secret_key
 let of_secret_key = Sodium.Box.Bigbytes.of_secret_key
 let to_public_key = Sodium.Box.Bigbytes.to_public_key
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
index d870b0bb2..c1d1b9e47 100644
--- a/src/utils/crypto_box.mli
+++ b/src/utils/crypto_box.mli
@@ -17,7 +17,7 @@ val random_keypair : unit -> secret_key * public_key
 val random_nonce : unit -> nonce
 val increment_nonce : ?step:int -> nonce -> nonce
 val box : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
-val box_open : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t
+val box_open : secret_key -> public_key -> MBytes.t -> nonce -> MBytes.t option
 val to_secret_key : MBytes.t -> secret_key
 val of_secret_key : secret_key -> MBytes.t
 val to_public_key : MBytes.t -> public_key

From 56e5fc3213aadc2652f68eb21dbfe5781f51da9d Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Mon, 7 Nov 2016 14:50:22 -0800
Subject: [PATCH 10/12] encrypt arbitrary net frames

---
 src/node/net/p2p.ml | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index e6e97f961..9452db98e 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -181,7 +181,7 @@ and peer = {
   last_seen : unit -> float ;
   disconnect : unit -> unit Lwt.t;
   send : packet -> unit Lwt.t ;
-  send_encr : MBytes.t -> unit Lwt.t ;
+  send_encr : frame -> unit Lwt.t ;
 }
 
 (* The (internal) type of network events, those dispatched from peer
@@ -357,7 +357,7 @@ let connect_to_peer config limits my_gid my_public_key my_nonce my_secret_key so
     let disconnect () = cancel () in
     let send p = send_packet socket p >>= fun _ -> return () in
     let send_encr msg =
-      let msg_encr = Crypto_box.box my_secret_key public_key msg (current_nonce ()) in
+      let msg_encr = Crypto_box.box my_secret_key public_key (to_raw msg) (current_nonce ()) in
       let packet = Box msg_encr in
       next_nonce (); send_packet socket packet >>= fun _ -> return () in
     (* net object construction *)
@@ -388,7 +388,10 @@ let connect_to_peer config limits my_gid my_public_key my_nonce my_secret_key so
             |> function
               | None -> debug "(%a) cannot decrypt message (from peer) %a @ %a:%d"
                   pp_gid my_gid pp_gid gid Ipaddr.pp_hum addr port ; receiver ()
-              | Some msg -> push (Recv (peer, [B msg])) ; receiver ()
+              | Some bytes -> of_raw bytes |> function
+                | None -> debug "(%a) cannot decode message (from peer) %a @ %a:%d"
+                    pp_gid my_gid pp_gid gid Ipaddr.pp_hum addr port ; receiver ()
+                | Some msg -> push (Recv (peer, msg)) ; receiver ()
     in
     (* The polling loop *)
     let rec pulse_monitor ping =

From e9ff110d08680d856de4a8f92c13d158fbb26d17 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Tue, 8 Nov 2016 18:18:09 -0800
Subject: [PATCH 11/12] proof of work start

---
 src/node/net/p2p.ml      | 1 +
 src/utils/crypto_box.ml  | 7 +++++++
 src/utils/crypto_box.mli | 3 +++
 3 files changed, 11 insertions(+)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index 9452db98e..6d8e0de68 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -174,6 +174,7 @@ type net = {
 and peer = {
   gid : gid ;
   public_key : Crypto_box.public_key ;
+  (*proof_of_work_nonce : Crypto_box.nonce ;*)
   current_nonce : unit -> Crypto_box.nonce ;
   point : point ;
   listening_port : port option ;
diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index 8931436c9..c0cc4248e 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -13,6 +13,7 @@ type secret_key = Sodium.Box.secret_key
 type public_key = Sodium.Box.public_key
 type channel_key = Sodium.Box.channel_key
 type nonce = Sodium.Box.nonce
+type difficulty = int
 
 let random_keypair = Sodium.Box.random_keypair
 let random_nonce = Sodium.Box.random_nonce
@@ -27,3 +28,9 @@ let to_public_key = Sodium.Box.Bigbytes.to_public_key
 let of_public_key = Sodium.Box.Bigbytes.of_public_key
 let to_nonce = Sodium.Box.Bigbytes.to_nonce
 let of_nonce = Sodium.Box.Bigbytes.of_nonce
+let check_proof_of_work pk nonce difficulty = assert false
+let generate_proof_of_work pk difficulty =
+  let rec loop nonce =
+    if check_proof_of_work pk nonce difficulty then nonce
+    else loop (increment_nonce nonce) in
+  loop (random_nonce ())
diff --git a/src/utils/crypto_box.mli b/src/utils/crypto_box.mli
index c1d1b9e47..1bb45c606 100644
--- a/src/utils/crypto_box.mli
+++ b/src/utils/crypto_box.mli
@@ -12,6 +12,7 @@
 type secret_key
 type public_key
 type nonce
+type difficulty
 
 val random_keypair : unit -> secret_key * public_key
 val random_nonce : unit -> nonce
@@ -24,3 +25,5 @@ val to_public_key : MBytes.t -> public_key
 val of_public_key : public_key -> MBytes.t
 val to_nonce : MBytes.t -> nonce
 val of_nonce : nonce -> MBytes.t
+val check_proof_of_work : public_key -> nonce -> difficulty -> bool
+val generate_proof_of_work : public_key -> difficulty -> nonce

From 4cd86b7ca83e7a1775ea24227d8d5ab1062ddcc3 Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Wed, 9 Nov 2016 18:29:57 -0800
Subject: [PATCH 12/12] check proof of work

---
 src/utils/crypto_box.ml | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/utils/crypto_box.ml b/src/utils/crypto_box.ml
index c0cc4248e..d5190d5fd 100644
--- a/src/utils/crypto_box.ml
+++ b/src/utils/crypto_box.ml
@@ -28,7 +28,20 @@ let to_public_key = Sodium.Box.Bigbytes.to_public_key
 let of_public_key = Sodium.Box.Bigbytes.of_public_key
 let to_nonce = Sodium.Box.Bigbytes.to_nonce
 let of_nonce = Sodium.Box.Bigbytes.of_nonce
-let check_proof_of_work pk nonce difficulty = assert false
+let check_proof_of_work pk nonce difficulty =
+  let hash_bytes l =
+    let hash = Cryptokit.Hash.sha256 () in
+    List.iter (fun b -> hash#add_string (MBytes.to_string b)) l;
+    let r = hash#result in hash#wipe; r in
+  let hash = hash_bytes [of_public_key pk; of_nonce nonce] in
+  let bytes = MBytes.of_string hash in
+  let len = MBytes.length bytes * 8 in
+  try
+    for i = len - 1 downto (len - difficulty) do
+      if MBytes.get_bool bytes i then raise Exit
+    done;
+    true
+  with Exit -> false
 let generate_proof_of_work pk difficulty =
   let rec loop nonce =
     if check_proof_of_work pk nonce difficulty then nonce