import struct from typing import Optional from binascii import hexlify, unhexlify from lbry.crypto.hash import sha512, double_sha256, ripemd160 from lbry.wallet.client.baseheader import BaseHeaders from lbry.wallet.client.util import ArithUint256 class Headers(BaseHeaders): header_size = 112 chunk_size = 10**16 max_target = 0x0000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff genesis_hash = b'9c89283ba0f3227f6c03b70216b9f665f0118d5e0fa729cedf4fb34d6a34f463' target_timespan = 150 checkpoint = (600_000, b'100b33ca3d0b86a48f0d6d6f30458a130ecb89d5affefe4afccb134d5a40f4c2') @property def claim_trie_root(self): return self[self.height]['claim_trie_root'] @staticmethod def serialize(header): return b''.join([ struct.pack(' ArithUint256: # https://github.com/lbryio/lbrycrd/blob/master/src/lbry.cpp if previous is None and current is None: return max_target if previous is None: previous = current actual_timespan = current['timestamp'] - previous['timestamp'] modulated_timespan = self.target_timespan + int((actual_timespan - self.target_timespan) / 8) minimum_timespan = self.target_timespan - int(self.target_timespan / 8) # 150 - 18 = 132 maximum_timespan = self.target_timespan + int(self.target_timespan / 2) # 150 + 75 = 225 clamped_timespan = max(minimum_timespan, min(modulated_timespan, maximum_timespan)) target = ArithUint256.from_compact(current['bits']) new_target = min(max_target, (target * clamped_timespan) / self.target_timespan) return new_target @classmethod def get_proof_of_work(cls, header_hash: bytes): return super().get_proof_of_work( cls.header_hash_to_pow_hash(header_hash) ) @staticmethod def header_hash_to_pow_hash(header_hash: bytes): header_hash_bytes = unhexlify(header_hash)[::-1] h = sha512(header_hash_bytes) pow_hash = double_sha256( ripemd160(h[:len(h) // 2]) + ripemd160(h[len(h) // 2:]) ) return hexlify(pow_hash[::-1]) class UnvalidatedHeaders(Headers): validate_difficulty = False max_target = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff genesis_hash = b'6e3fcf1299d4ec5d79c3a4c91d624a4acf9e2e173d95a1a0504f677669687556'