added farmer authentication method

dataserv/Farmer.py

@@ -1,8 +1,10 @@
 import json
 import hashlib
-from dataserv.run import db
+import binascii
+from dataserv.run import db, app
 from datetime import datetime
 from sqlalchemy import DateTime
+from btctxstore import BtcTxStore
 from dataserv.Validator import is_btc_address
 
 
@@ -17,7 +19,7 @@ class Farmer(db.Model):
     btc_addr = db.Column(db.String(35), unique=True)
     last_seen = db.Column(DateTime, default=datetime.utcnow)
     height = db.Column(db.Integer, default=0)
-    last_message_hash = db.Column(db.String(64), unique=True)  # sha256sum
+    authentication_nonce = db.Column(db.Integer, default=0)
 
     def __init__(self, btc_addr, last_seen=None):
         """
@@ -32,6 +34,19 @@ def __init__(self, btc_addr, last_seen=None):
     def __repr__(self):
         return '<Farmer BTC Address: %r>' % self.btc_addr
 
+    def authenticate(self, btc_addr, signature):
+        farmer = self.lookup()
+
+        # verify signature
+        message = app.config["ADDRESS"] + "-" + farmer.authentication_nonce
+        data = binascii.hexlify(message)
+        if not BtcTxStore().verify_signature(address, signature, data):
+            raise ValueError("Invalid signature!")
+
+        # increment authentication nonce
+        farmer.authentication_nonce = authentication_nonce + 1
+        db.session.commit()
+
     def is_btc_address(self):
         """Check if the address is a valid Bitcoin public key."""
         return is_btc_address(self.btc_addr)
@@ -100,6 +115,7 @@ def to_json(self):
         payload = {
             "btc_addr": self.btc_addr,
             "last_seen": (datetime.utcnow() - self.last_seen).seconds,
-            "height": self.height
+            "height": self.height,
+            "authentication_nonce": self.authentication_nonce,
         }
         return json.dumps(payload)

dataserv/config.py

@@ -3,3 +3,5 @@
 
 DATA_DIR = 'data/'
 BYTE_SIZE = 1024*1024*128  # 128 MB
+
+ADDRESS = "16ZcxFDdkVJR1P8GMNmWFyhS4EKrRMsWNG"  # unique per server address

requirements.txt

@@ -2,3 +2,4 @@ Flask == 0.10.1
 Flask-SQLAlchemy == 2.0
 RandomIO == 0.2.1
 partialhash == 1.1.0
+btctxstore == 4.1.2

tests/test_Farmer.py

@@ -100,7 +100,7 @@ def test_to_json(self):
         farmer.ping()
         farmer.set_height(50)
 
-        test_payload = u'{"height": 50, "btc_addr": "191GVvAaTRxLmz3rW3nU5jAV1rF186VxQc", "last_seen": 0}'
+        test_payload = u'{"authentication_nonce": 0, "height": 50, "btc_addr": "191GVvAaTRxLmz3rW3nU5jAV1rF186VxQc", "last_seen": 0}'
         test_json = json.loads(test_payload)
         call_payload = json.loads(farmer.to_json())
         self.assertEqual(test_json, call_payload)