From bf36429fd7dfdfe94c86b5e7d6e2c72d793c9f6b Mon Sep 17 00:00:00 2001
From: Piotr Lizonczyk <piotr.lizonczyk@gmail.com>
Date: Sun, 6 Aug 2017 00:04:16 +0200
Subject: [PATCH] * Adding handshake patterns * Adding token constants for
 handshake patterns

---
 noise/constants.py |  10 +++
 noise/patterns.py  | 161 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 171 insertions(+)
 create mode 100644 noise/patterns.py

diff --git a/noise/constants.py b/noise/constants.py
index b6da454..414cc11 100644
--- a/noise/constants.py
+++ b/noise/constants.py
@@ -1,2 +1,12 @@
 class Empty:
     pass
+
+
+# Handshake pattern tokens
+TOKEN_E = 'e'
+TOKEN_S = 's'
+TOKEN_EE = 'ee'
+TOKEN_ES = 'es'
+TOKEN_SE = 'se'
+TOKEN_SS = 'ss'
+TOKEN_PSK = 'psk'
diff --git a/noise/patterns.py b/noise/patterns.py
new file mode 100644
index 0000000..f3518de
--- /dev/null
+++ b/noise/patterns.py
@@ -0,0 +1,161 @@
+from noise.constants import TOKEN_E, TOKEN_S, TOKEN_EE, TOKEN_ES, TOKEN_SE, TOKEN_SS, TOKEN_PSK
+
+
+class Pattern(object):
+    """
+    TODO document
+    """
+    # As per specification, if both parties have pre-messages, the initiator is listed first. To reduce complexity,
+    # pre_messages shall be a list of two lists:
+    # the first for the initiator's pre-messages, the second for the responder
+    pre_messages = [
+        [],
+        []
+    ]
+    # TODO Comment
+    tokens = []
+
+
+# One-way patterns
+
+class PatternN(Pattern):
+    pre_messages = [
+        [],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES]
+    ]
+
+
+class PatternK(Pattern):
+    pre_messages = [
+        [TOKEN_S],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES, TOKEN_SS]
+    ]
+
+
+class PatternX(Pattern):
+    pre_messages = [
+        [],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES, TOKEN_S, TOKEN_SS]
+    ]
+
+
+# Interactive patterns
+
+class PatternNN(Pattern):
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE]
+    ]
+
+
+class PatternKN(Pattern):
+    pre_messages = [
+        [TOKEN_S],
+        []
+    ]
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE]
+    ]
+
+
+class PatternNK(Pattern):
+    pre_messages = [
+        [],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES],
+        [TOKEN_E, TOKEN_EE]
+    ]
+
+
+class PatternKK(Pattern):
+    pre_messages = [
+        [TOKEN_S],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES, TOKEN_SS],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE]
+    ]
+
+
+class PatternNX(Pattern):
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE, TOKEN_S, TOKEN_ES]
+    ]
+
+
+class PatternKX(Pattern):
+    pre_messages = [
+        [TOKEN_S],
+        []
+    ]
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE, TOKEN_S, TOKEN_ES]
+    ]
+
+
+class PatternXN(Pattern):
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE],
+        [TOKEN_S, TOKEN_SE]
+    ]
+
+
+class PatternIN(Pattern):
+    tokens = [
+        [TOKEN_E, TOKEN_S],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE]
+    ]
+
+
+class PatternXK(Pattern):
+    pre_messages = [
+        [],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES],
+        [TOKEN_E, TOKEN_EE],
+        [TOKEN_S, TOKEN_SE]
+    ]
+
+
+class PatternIK(Pattern):
+    pre_messages = [
+        [],
+        [TOKEN_S]
+    ]
+    tokens = [
+        [TOKEN_E, TOKEN_ES, TOKEN_S, TOKEN_SS],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE]
+    ]
+
+
+class PatternXX(Pattern):
+    tokens = [
+        [TOKEN_E],
+        [TOKEN_E, TOKEN_EE, TOKEN_S, TOKEN_ES],
+        [TOKEN_S, TOKEN_SE]
+    ]
+
+
+class PatternIX(Pattern):
+    tokens = [
+        [TOKEN_E, TOKEN_S],
+        [TOKEN_E, TOKEN_EE, TOKEN_SE, TOKEN_S, TOKEN_ES]
+    ]