message: PoS block creation uniqueness.
diff: @@ -453,6 +453,13 @@ class CBlockHeader():
  self.calc_sha256()
  return self.sha256
  + # PIV Uniqueness
  + def get_uniqueness(self, prevout):
  + r = b""
  + r += struct.pack("<I", prevout.n)
  + r += ser_uint256(prevout.hash)
  + return r
  +
  def solve_stake(self, stakeModifier, prevouts):
  target0 = uint256_from_compact(self.nBits)
  loop = True
  @@ -467,7 +474,7 @@ class CBlockHeader():
  if isinstance(prevout, str):
  data += ser_uint256(uint256_from_str(bytes.fromhex(prevout)))
  else:
  - data += prevout.serialize()
  + data += self.get_uniqueness(prevout)
  data += struct.pack("<I", self.nTime)
  posHash = uint256_from_str(hash256(data))
  if posHash <= target:
  