def get_challenge(self, block: FullBlock) -> Optional[Challenge]:
if block.proof_of_time is None:
return None
if block.prev_header_hash not in self.headers and block.height > 0:
return None
prev_challenge_hash = block.proof_of_space.challenge_hash
new_difficulty: Optional[uint64]
if (
block.height + 1
) % self.constants.DIFFICULTY_EPOCH == self.constants.DIFFICULTY_DELAY:
new_difficulty = get_next_difficulty(
self.constants, self.headers, self.height_to_hash, block.header
)
else:
new_difficulty = None
return Challenge(
prev_challenge_hash,
std_hash(
block.proof_of_space.get_hash() + block.proof_of_time.output.get_hash()
),
new_difficulty,
)
def get_next_difficulty(self, header_hash: bytes32) -> uint64:
return get_next_difficulty(self.constants, self.headers,
self.height_to_hash, header_hash)
async def validate_unfinished_block_header(
constants: ConsensusConstants,
headers: Dict[bytes32, Header],
height_to_hash: Dict[uint32, bytes32],
block_header: Header,
proof_of_space: ProofOfSpace,
prev_header_block: Optional[HeaderBlock],
pre_validated: bool = False,
pos_quality_string: bytes32 = None,
) -> Tuple[Optional[Err], Optional[uint64]]:
"""
Block validation algorithm. Returns the number of VDF iterations that this block's
proof of time must have, if the candidate block is fully valid (except for proof of
time). The same as validate_block, but without proof of time and challenge validation.
If the block is invalid, an error code is returned.
Does NOT validate transactions and fees.
"""
if not pre_validated:
# 1. The hash of the proof of space must match header_data.proof_of_space_hash
if proof_of_space.get_hash() != block_header.data.proof_of_space_hash:
return (Err.INVALID_POSPACE_HASH, None)
# 2. The coinbase signature must be valid, according the the pool public key
# TODO: change numbers
# 3. Check harvester signature of header data is valid based on harvester key
validates = blspy.AugSchemeMPL.verify(
proof_of_space.plot_public_key,
block_header.data.get_hash(),
block_header.plot_signature,
)
if not validates:
return (Err.INVALID_PLOT_SIGNATURE, None)
# 4. If not genesis, the previous block must exist
if prev_header_block is not None and block_header.prev_header_hash not in headers:
return (Err.DOES_NOT_EXTEND, None)
# 5. If not genesis, the timestamp must be >= the average timestamp of last 11 blocks
# and less than 2 hours in the future (if block height < 11, average all previous blocks).
# Average is the sum, int diveded by the number of timestamps
if prev_header_block is not None:
last_timestamps: List[uint64] = []
curr = prev_header_block.header
while len(last_timestamps) < constants.NUMBER_OF_TIMESTAMPS:
last_timestamps.append(curr.data.timestamp)
fetched = headers.get(curr.prev_header_hash, None)
if not fetched:
break
curr = fetched
if len(last_timestamps) != constants.NUMBER_OF_TIMESTAMPS:
# For blocks 1 to 10, average timestamps of all previous blocks
assert curr.height == 0
prev_time: uint64 = uint64(
int(sum(last_timestamps) // len(last_timestamps)))
if block_header.data.timestamp < prev_time:
return (Err.TIMESTAMP_TOO_FAR_IN_PAST, None)
if block_header.data.timestamp > time.time(
) + constants.MAX_FUTURE_TIME:
return (Err.TIMESTAMP_TOO_FAR_IN_FUTURE, None)
# 7. Extension data must be valid, if any is present
# Compute challenge of parent
challenge_hash: bytes32
if prev_header_block is not None:
challenge: Challenge = prev_header_block.challenge
challenge_hash = challenge.get_hash()
# 8. Check challenge hash of prev is the same as in pos
if challenge_hash != proof_of_space.challenge_hash:
return (Err.INVALID_POSPACE_CHALLENGE, None)
# 10. The proof of space must be valid on the challenge
if pos_quality_string is None:
pos_quality_string = proof_of_space.verify_and_get_quality_string(
constants.NUMBER_ZERO_BITS_CHALLENGE_SIG)
if not pos_quality_string:
return (Err.INVALID_POSPACE, None)
if prev_header_block is not None:
# 11. If not genesis, the height on the previous block must be one less than on this block
if block_header.height != prev_header_block.height + 1:
return (Err.INVALID_HEIGHT, None)
else:
# 12. If genesis, the height must be 0
if block_header.height != 0:
return (Err.INVALID_HEIGHT, None)
# 13. The pool max height must be valid
if (block_header.data.pool_target.max_height != 0 and
block_header.data.pool_target.max_height < block_header.height):
return (Err.INVALID_POOL_TARGET, None)
difficulty: uint64
if prev_header_block is not None:
difficulty = get_next_difficulty(constants, headers, height_to_hash,
prev_header_block.header)
min_iters = get_next_min_iters(constants, headers, height_to_hash,
prev_header_block)
else:
difficulty = uint64(constants.DIFFICULTY_STARTING)
min_iters = uint64(constants.MIN_ITERS_STARTING)
number_of_iters: uint64 = calculate_iterations_quality(
pos_quality_string,
proof_of_space.size,
difficulty,
min_iters,
)
assert count_significant_bits(difficulty) <= constants.SIGNIFICANT_BITS
assert count_significant_bits(min_iters) <= constants.SIGNIFICANT_BITS
if prev_header_block is not None:
# 17. If not genesis, the total weight must be the parent weight + difficulty
if block_header.weight != prev_header_block.weight + difficulty:
return (Err.INVALID_WEIGHT, None)
# 18. If not genesis, the total iters must be parent iters + number_iters
if (block_header.data.total_iters !=
prev_header_block.header.data.total_iters + number_of_iters):
return (Err.INVALID_TOTAL_ITERS, None)
else:
# 19. If genesis, the total weight must be starting difficulty
if block_header.weight != difficulty:
return (Err.INVALID_WEIGHT, None)
# 20. If genesis, the total iters must be number iters
if block_header.data.total_iters != number_of_iters:
return (Err.INVALID_TOTAL_ITERS, None)
return (None, number_of_iters)
async def validate_unfinished_block_header(
constants: Dict,
headers: Dict[bytes32, Header],
height_to_hash: Dict[uint32, bytes32],
block_header: Header,
proof_of_space: ProofOfSpace,
prev_header_block: Optional[HeaderBlock],
pre_validated: bool = False,
pos_quality_string: bytes32 = None,
) -> Tuple[Optional[Err], Optional[uint64]]:
"""
Block validation algorithm. Returns the number of VDF iterations that this block's
proof of time must have, if the candidate block is fully valid (except for proof of
time). The same as validate_block, but without proof of time and challenge validation.
If the block is invalid, an error code is returned.
Does NOT validate transactions and fees.
"""
if not pre_validated:
# 1. The hash of the proof of space must match header_data.proof_of_space_hash
if proof_of_space.get_hash() != block_header.data.proof_of_space_hash:
return (Err.INVALID_POSPACE_HASH, None)
# 2. The coinbase signature must be valid, according the the pool public key
pair = block_header.data.coinbase_signature.PkMessagePair(
proof_of_space.pool_pubkey,
block_header.data.coinbase.name(),
)
if not block_header.data.coinbase_signature.validate([pair]):
return (Err.INVALID_COINBASE_SIGNATURE, None)
# 3. Check harvester signature of header data is valid based on harvester key
if not block_header.harvester_signature.verify(
[blspy.Util.hash256(block_header.data.get_hash())],
[proof_of_space.plot_pubkey],
):
return (Err.INVALID_HARVESTER_SIGNATURE, None)
# 4. If not genesis, the previous block must exist
if prev_header_block is not None and block_header.prev_header_hash not in headers:
return (Err.DOES_NOT_EXTEND, None)
# 5. If not genesis, the timestamp must be >= the average timestamp of last 11 blocks
# and less than 2 hours in the future (if block height < 11, average all previous blocks).
# Average is the sum, int diveded by the number of timestamps
if prev_header_block is not None:
last_timestamps: List[uint64] = []
curr = prev_header_block.header
while len(last_timestamps) < constants["NUMBER_OF_TIMESTAMPS"]:
last_timestamps.append(curr.data.timestamp)
fetched = headers.get(curr.prev_header_hash, None)
if not fetched:
break
curr = fetched
if len(last_timestamps) != constants["NUMBER_OF_TIMESTAMPS"]:
# For blocks 1 to 10, average timestamps of all previous blocks
assert curr.height == 0
prev_time: uint64 = uint64(
int(sum(last_timestamps) // len(last_timestamps)))
if block_header.data.timestamp < prev_time:
return (Err.TIMESTAMP_TOO_FAR_IN_PAST, None)
if block_header.data.timestamp > time.time(
) + constants["MAX_FUTURE_TIME"]:
return (Err.TIMESTAMP_TOO_FAR_IN_FUTURE, None)
# 7. Extension data must be valid, if any is present
# Compute challenge of parent
challenge_hash: bytes32
if prev_header_block is not None:
challenge: Challenge = prev_header_block.challenge
challenge_hash = challenge.get_hash()
# 8. Check challenge hash of prev is the same as in pos
if challenge_hash != proof_of_space.challenge_hash:
return (Err.INVALID_POSPACE_CHALLENGE, None)
# 10. The proof of space must be valid on the challenge
if pos_quality_string is None:
pos_quality_string = proof_of_space.verify_and_get_quality_string()
if not pos_quality_string:
return (Err.INVALID_POSPACE, None)
if prev_header_block is not None:
# 11. If not genesis, the height on the previous block must be one less than on this block
if block_header.height != prev_header_block.height + 1:
return (Err.INVALID_HEIGHT, None)
else:
# 12. If genesis, the height must be 0
if block_header.height != 0:
return (Err.INVALID_HEIGHT, None)
# 13. The coinbase reward must match the block schedule
coinbase_reward = calculate_block_reward(block_header.height)
if coinbase_reward != block_header.data.coinbase.amount:
return (Err.INVALID_COINBASE_AMOUNT, None)
# 13b. The coinbase parent id must be the height
if block_header.data.coinbase.parent_coin_info != block_header.height.to_bytes(
32, "big"):
return (Err.INVALID_COINBASE_PARENT, None)
# 13c. The fees coin parent id must be hash(hash(height))
if block_header.data.fees_coin.parent_coin_info != std_hash(
std_hash(uint32(block_header.height))):
return (Err.INVALID_FEES_COIN_PARENT, None)
difficulty: uint64
if prev_header_block is not None:
difficulty = get_next_difficulty(constants, headers, height_to_hash,
prev_header_block.header)
min_iters = get_next_min_iters(constants, headers, height_to_hash,
prev_header_block)
else:
difficulty = uint64(constants["DIFFICULTY_STARTING"])
min_iters = uint64(constants["MIN_ITERS_STARTING"])
number_of_iters: uint64 = calculate_iterations_quality(
pos_quality_string,
proof_of_space.size,
difficulty,
min_iters,
)
assert count_significant_bits(difficulty) <= constants["SIGNIFICANT_BITS"]
assert count_significant_bits(min_iters) <= constants["SIGNIFICANT_BITS"]
if prev_header_block is not None:
# 17. If not genesis, the total weight must be the parent weight + difficulty
if block_header.weight != prev_header_block.weight + difficulty:
return (Err.INVALID_WEIGHT, None)
# 18. If not genesis, the total iters must be parent iters + number_iters
if (block_header.data.total_iters !=
prev_header_block.header.data.total_iters + number_of_iters):
return (Err.INVALID_TOTAL_ITERS, None)
else:
# 19. If genesis, the total weight must be starting difficulty
if block_header.weight != difficulty:
return (Err.INVALID_WEIGHT, None)
# 20. If genesis, the total iters must be number iters
if block_header.data.total_iters != number_of_iters:
return (Err.INVALID_TOTAL_ITERS, None)
return (None, number_of_iters)