dilation side needs to be 16-chars to match transit relay

src/wormhole/_dilation/connector.py

@@ -28,7 +28,9 @@ from ._noise import NoiseConnection
 
 def build_sided_relay_handshake(key, side):
     assert isinstance(side, type(u""))
-    assert len(side) == 8 * 2
+    # magic-wormhole-transit-relay expects a specific layout for the
+    # handshake message: "please relay {64} for side {16}\n"
+    assert len(side) == 8 * 2, side
     token = HKDF(key, 32, CTXinfo=b"transit_relay_token")
     return (b"please relay " + hexlify(token) +
             b" for side " + side.encode("ascii") + b"\n")

src/wormhole/_dilation/manager.py

@@ -65,7 +65,7 @@ class EndpointRecord(Sequence):
         return (self.control, self.connect, self.listen)[n]
 
 def make_side():
-    return bytes_to_hexstr(os.urandom(6))
+    return bytes_to_hexstr(os.urandom(8))
 
 
 # new scheme:

src/wormhole/test/dilate/test_manager.py

@@ -216,7 +216,7 @@ class TestManager(unittest.TestCase):
     def test_make_side(self):
         side = make_side()
         self.assertEqual(type(side), type(u""))
-        self.assertEqual(len(side), 2 * 6)
+        self.assertEqual(len(side), 2 * 8)
 
     def test_create(self):
         m, h = make_manager()