Added more Policy and PolicyGroup logic. Now conforms to @tux's crypto APIs.

nkms/crypto/hash.py

@@ -0,0 +1,10 @@
+import random
+
+# TODO: Replace these with actual hash functions.
+
+def signature_hash(hash_input):
+    return random.getrandbits(128)
+
+
+def content_hash(hash_input):
+    return random.getrandbits(128)

nkms/crypto/pre/keygen.py

@@ -0,0 +1,12 @@
+# TODO: Make this actually work.
+def generate_re_encryption_keys(seckey_enc_alice,
+                                pubkey_enc_bob,
+                                m,
+                                n):
+    kfrags = [
+        'sfasdfsd9',
+        'dfasd09fi',
+        'sdfksd3f9',
+    ]
+
+    return kfrags

nkms/policy/constants.py

@@ -0,0 +1 @@
+UNKNOWN_KFRAG = 550

nkms/policy/models.py

@@ -1,5 +1,6 @@
-from nkms.crypto.pre.keys import generate_re_encryption_keys
+from nkms.crypto.hash import content_hash
-from nkms.crypto import nkms_hash
+from nkms.crypto.pre.keygen import generate_re_encryption_keys
+from nkms.policy.constants import UNKNOWN_KFRAG
 
 
 class PolicyGroup(object):
@@ -7,38 +8,42 @@ class PolicyGroup(object):
     The terms and conditions by which Alice shares with Bob.
     """
 
-    def __init__(self):
+    def __init__(self, policies=None):
-        self.policies = []
+        self.policies = policies or []
 
-    def craft(self,
+    @staticmethod
-                keychain_alice: "KeyChain",
+    def craft(keychain_alice: "KeyChain",
-                pubkey_enc_bob: tuple,
+              pubkey_enc_bob: tuple,
-                uri: bytes,
+              uri: bytes,
-                m: int,
+              m: int,
-                n: int
+              n: int
-                ):
+              ):
         """
         Alice dictates a new group of policies.
         """
-        re_enc_keys = generate_re_encryption_keys(keychain_alice.seckey_end,
+        re_enc_keys = generate_re_encryption_keys(keychain_alice.enc_keypair.priv_key,
                                                   pubkey_enc_bob,
                                                   m,
                                                   n)
+        policies = []
         for kfrag_id, key in enumerate(re_enc_keys):
             policy = Policy.from_alice(
                 key,  # Bob won't know this.
-                keychain_alice.pubkey_sig,
+                keychain_alice.sig_keypair.pub_key,
                 pubkey_enc_bob,
                 uri,  # Ursula won't know this.
                 kfrag_id,
             )
-            self.policies.append(policy)
+            policies.append(policy)
+
+        return PolicyGroup(policies)
+
 
     def transmit(self, networky_stuff):
         for policy in self.policies:
-            policy_offer = policy.craft_offer()
+            policy_offer = policy.craft_offer(networky_stuff)
             result = networky_stuff.transmit_offer(policy.ursula, policy_offer)
-            if result.was_accepted():
+            if result.was_accepted:
                 policy.update_treasure_map(result)
 
 
@@ -55,6 +60,11 @@ class Policy(object):
     ursula = None
     hashed_part = None
 
+    def __init__(self, kfrag=UNKNOWN_KFRAG, challenge_size=20):
+        self.kfrag = kfrag
+        self.challenge_size = challenge_size
+        self.treasure_map = []
+
     @staticmethod
     def from_alice(kfrag,
                    pubkey_sig_alice,
@@ -62,16 +72,16 @@ class Policy(object):
                    uri,
                    kfrag_id
                    ):
-
+        policy = Policy(kfrag)
-        policy = Policy()
+        policy.generate_challenge_pack()
-        policy.generate_challenge_pack(kfrag)
+        policy.hash(pubkey_sig_alice=pubkey_sig_alice, hash_input=(pubkey_enc_bob, uri, kfrag_id))
-        policy.hash(pubkey_enc_bob, uri, kfrag_id, pubkey_sig_alice=pubkey_sig_alice)
 
         return policy
 
-    def hash(self, pubkey_sig_alice, *args):
+    def hash(self, pubkey_sig_alice, hash_input):
-        self.hashed_part = nkms_hash(*args)
+        self.hashed_part = content_hash(hash_input)
-        self.id = nkms_hash(pubkey_sig_alice, self.hashed_part)
+        hash_input_for_id = (pubkey_sig_alice, self.hashed_part)
+        self.id = content_hash(hash_input_for_id)
         return self.id
 
     def craft_offer(self, networky_stuff):
@@ -79,4 +89,18 @@ class Policy(object):
         Find an Ursula and craft an offer for her.
         """
         self.ursula = networky_stuff.find_ursula(self.id, self.hashed_part)
-        return self.ursula.encrypt_for(self.kfrag, self.challenge_pack, self.treasure_map)
+        return self.ursula.encrypt_for((self.kfrag, self.challenge_pack, self.treasure_map))
+
+    def generate_challenge_pack(self):
+        if self.kfrag == UNKNOWN_KFRAG:
+            raise TypeError("Can't generate a challenge pack unless we know the kfrag.  Are you Alice?")
+
+        # TODO: make this work instead of being random.
+        import random
+        self.challenge_pack = [(random.getrandbits(32), random.getrandbits(32)) for x in range(self.challenge_size)]
+        return True
+
+    def update_treasure_map(self, policy_offer_result):
+        # TODO: parse the result and add the node information to the treasure map.
+        self.treasure_map.append(policy_offer_result)
+

tests/test_network_actors.py

@@ -1,22 +1,45 @@
-from nkms.crypto.keys import KeyChain
+from nkms.crypto.keyring import KeyRing
-
 from nkms.policy.models import PolicyGroup
 
 
+class MockUrsula(object):
+    def encrypt_for(self, payload):
+        # TODO: Make this a testable result
+        import random
+        return random.getrandbits(32)
+
+
+
+class MockPolicyOfferResponse(object):
+    was_accepted = True
+
+
+class MockNetworkyStuff(object):
+
+    def transmit_offer(self, ursula, policy_offer):
+        return MockPolicyOfferResponse()
+
+    def find_ursula(self, id, hashed_part):
+        return MockUrsula()
+
+
+
+
+
 def test_alice_has_ursulas_public_key_and_uses_it_to_encode_policy_payload():
-    keychain_alice = KeyChain()
+    keychain_alice = KeyRing()
-    keychain_bob = KeyChain()
+    keychain_bob = KeyRing()
-    keychain_ursula = KeyChain()
+    keychain_ursula = KeyRing()
 
     # For example, a hashed path.
     resource_id = b"as098duasdlkj213098asf"
-    kfrag_id = 74
 
     # Alice runs this to get a policy object.
-    policy_group = PolicyGroup.craft(keychain_alice.pubkey_sig,
+    policy_group = PolicyGroup.craft(keychain_alice,
-                                       keychain_bob.pubkey_sig,
+                                     keychain_bob.enc_keypair.pub_key,
-                                       resource_id,
+                                     resource_id,
-                                       kfrag_id
+                                     m=20,
-                                       )
+                                     n=50
-
+                                     )
-    policy_group.transmit()
+    networky_stuff = MockNetworkyStuff()
+    policy_group.transmit(networky_stuff)