fix derive_secret

lib/lnbase.py

@@ -317,31 +317,16 @@ def derive_blinded_pubkey(basepoint, per_commitment_point):
     return point_to_ser(k1 + k2)
 
 
-def get_per_commitment_secret_from_seed(seed: int, i: int) -> int:
+def get_per_commitment_secret_from_seed(seed: int, bits: int, i: int) -> int:
     """Generate per commitment secret."""
 
-
-    #seed ^= 1
-    #pcs_bytes = seed.to_bytes(byteorder="big", length=32)
-    #print(bh2u(pcs_bytes))
-    #return int.from_bytes(hashlib.sha256(pcs_bytes[::-1]).digest(), byteorder="big")
-
-    #tmp = seed.to_bytes(byteorder="big", length=32)
-    #seed = int.from_bytes(tmp[::-1], byteorder="big")
-
     per_commitment_secret = seed
-    print('get_per_commitment_secret_from_seed() per_commitment_secret', per_commitment_secret)
+    for bitindex in range(bits, -1, -1):  # 47, 46, ..., 0
-    print('get_per_commitment_secret_from_seed() i', i)
-    for bitindex in range(47, -1, -1):  # 47, 46, ..., 0
         mask = 1 << bitindex
         if i & mask:
-            print('get_per_commitment_secret_from_seed() bitindex, mask', bitindex, mask)
+            pcs_bytes = bytearray(per_commitment_secret.to_bytes(byteorder="big", length=32))
-            print('get_per_commitment_secret_from_seed() branch entered')
+            pcs_bytes[bitindex // 8] ^= 1 << (bitindex % 8)
-            per_commitment_secret ^= mask
+            per_commitment_secret = int.from_bytes(bitcoin.sha256(pcs_bytes), byteorder="big")
-            print('get_per_commitment_secret_from_seed() per_commitment_secret br1', per_commitment_secret)
-            pcs_bytes = per_commitment_secret.to_bytes(byteorder="big", length=32)
-            per_commitment_secret = int.from_bytes(bitcoin.sha256(pcs_bytes[::-1]), byteorder="big")
-            print('get_per_commitment_secret_from_seed() per_commitment_secret br2', per_commitment_secret)
     return per_commitment_secret
 
 

lib/tests/test_lnbase.py

@@ -234,14 +234,14 @@ class Test_LNBase(unittest.TestCase):
 
     def test_per_commitment_secret_from_seed(self):
         self.assertEqual(bh2u(0x915c75942a26bb3a433a8ce2cb0427c29ec6c1775cfc78328b57f6ba7bfeaa9c.to_bytes(byteorder="big", length=32)),
-                         bh2u(get_per_commitment_secret_from_seed(0x0101010101010101010101010101010101010101010101010101010101010101, 1).to_bytes(byteorder="big", length=32)))
+                         bh2u(get_per_commitment_secret_from_seed(0x0101010101010101010101010101010101010101010101010101010101010101, 47, 1).to_bytes(byteorder="big", length=32)))
 
         self.assertEqual(bh2u(0x02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148.to_bytes(byteorder="big", length=32)),
-                         bh2u(get_per_commitment_secret_from_seed(0x0000000000000000000000000000000000000000000000000000000000000000, 281474976710655).to_bytes(byteorder="big", length=32)))
+                         bh2u(get_per_commitment_secret_from_seed(0x0000000000000000000000000000000000000000000000000000000000000000, 47, 281474976710655).to_bytes(byteorder="big", length=32)))
-        #self.assertEqual(0x7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc,
+        self.assertEqual(0x7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc,
-        #                 get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 281474976710655))
+                         get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 47, 281474976710655))
-        #self.assertEqual(0x56f4008fb007ca9acf0e15b054d5c9fd12ee06cea347914ddbaed70d1c13a528,
+        self.assertEqual(0x56f4008fb007ca9acf0e15b054d5c9fd12ee06cea347914ddbaed70d1c13a528,
-        #                 get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 0xaaaaaaaaaaa))
+                         get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 47, 0xaaaaaaaaaaa))
-        #self.assertEqual(0x9015daaeb06dba4ccc05b91b2f73bd54405f2be9f217fbacd3c5ac2e62327d31,
+        self.assertEqual(0x9015daaeb06dba4ccc05b91b2f73bd54405f2be9f217fbacd3c5ac2e62327d31,
-        #                 get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 0x555555555555))
+                         get_per_commitment_secret_from_seed(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 47, 0x555555555555))