Deterministic Seeding Function

dataserv/Challenge.py

@@ -1,16 +1,27 @@
 import random
+from dataserv.Farmer import sha256
+
 
 class Challenge:
-    def seed_list(self, height):
+    def __init__(self, btc_addr, height):
+        self.btc_addr = btc_addr
+        self.height = height
+
+        self.seeds = self.gen_seeds()
+        self.challenge = None
+
+    def gen_seeds(self):
         """Generate a list of seeds for challenges based on the Bitcoin address."""
         seeds = []
         last_seed = sha256(self.btc_addr)
-        for i in range(height+1):
+        for i in range(self.height):
             seeds.append(last_seed)
             last_seed =sha256(last_seed)
         return seeds
 
-    def gen_challenge(self):
+    def pick_seed(self):
         """Generate a random challenge for the Farmer."""
-        iter_seed = random.randrange(0, len(app.config['SEED_HEIGHT']))
-        seeds = self.seed_list(app.config['SEED_HEIGHT'])
+        return random.choice(self.seeds)
+
+    def get_seeds(self):
+        return self.seeds

dataserv/Farmer.py

@@ -24,7 +24,7 @@ class Farmer(db.Model):
     last_seen = db.Column(DateTime, default=datetime.utcnow)
     last_audit = db.Column(DateTime, default=datetime.utcnow)
 
-    iter_seed = db.Column(db.Integer)
+    seed = db.Column(db.Integer)
     response = db.Column(db.String(128))
 
     def __init__(self, btc_addr, last_seen=None, last_audit=None):

tests/test_Challenge.py

@@ -0,0 +1,21 @@
+import unittest
+from dataserv.Challenge import Challenge
+
+class ChallengeTest(unittest.TestCase):
+
+    def test_seeds(self):
+        addr = '191GVvAaTRxLmz3rW3nU5jAV1rF186VxQc'
+        chal = Challenge(addr, 100)
+
+        iter0 = '66357e60899acae95ce1e31def3d7b32a73d34b2f12ece73cdca025a26e17e32'
+        iter3 = '96a6cb8668775a1751d7cf1d59cd0a8d3bc67e8ed5e6f5fce0376d5e04284071'
+
+        seeds = chal.get_seeds()
+        self.assertEqual(len(seeds), 100)
+        self.assertEqual(iter0, seeds[0])
+        self.assertEqual(iter3, seeds[3])
+
+    def test_challenge(self):
+        addr = '191GVvAaTRxLmz3rW3nU5jAV1rF186VxQc'
+        chal = Challenge(addr, 100)
+        self.assertTrue(chal.pick_seed() in chal.get_seeds())