《区块链编程》第十一章
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文章目录
《区块链编程》第十一章
简单支付验证
练习1
p180
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 10:43:44
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:00:29
from helper import hash256
def merkle_parent(hash1, hash2):
'''Takes the binary hashes and calculates the hash256'''
return hash256(hash1 + hash2)
hash0 = bytes.fromhex('c117ea8ec828342f4dfb0ad6bd140e03a50720ece40169ee38b\
dc15d9eb64cf5')
hash1 = bytes.fromhex('c131474164b412e3406696da1ee20ab0fc9bf41c8f05fa8ceea\
7a08d672d7cc5')
print(merkle_parent(hash0, hash1).hex())
测试
8b30c5ba100f6f2e5ad1e2a742e5020491240f8eb514fe97c713c31718ad7ecd
[Finished in 318ms]
练习2
p181
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 10:53:22
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:06:46
from helper import merkle_parent
def merkel_parent_level(hashes):
'''Takes a list of binary hashes and returns a list that's half
the length'''
if len(hashes) == 1:
raise RuntimeError('Cannot take a parent level with only 1 item')
if len(hashes) % 2 == 1:
hashes.append(hashes[-1])
parent_level = []
for i in range(0, len(hashes), 2):
parent = merkle_parent(hashes[i], hashes[i + 1])
parent_level.append(parent)
return parent_level
hex_hashes = [
'c117ea8ec828342f4dfb0ad6bd140e03a50720ece40169ee38bdc15d9eb64cf5',
'c131474164b412e3406696da1ee20ab0fc9bf41c8f05fa8ceea7a08d672d7cc5',
'f391da6ecfeed1814efae39e7fcb3838ae0b02c02ae7d0a5848a66947c0727b0',
'3d238a92a94532b946c90e19c49351c763696cff3db400485b813aecb8a13181',
'10092f2633be5f3ce349bf9ddbde36caa3dd10dfa0ec8106bce23acbff637dae',
]
hashes = [bytes.fromhex(h) for h in hex_hashes]
level = merkel_parent_level(hashes)
for h in level:
print(h.hex())
测试
8b30c5ba100f6f2e5ad1e2a742e5020491240f8eb514fe97c713c31718ad7ecd
7f4e6f9e224e20fda0ae4c44114237f97cd35aca38d83081c9bfd41feb907800
3ecf6115380c77e8aae56660f5634982ee897351ba906a6837d15ebc3a225df0
[Finished in 323ms]
练习3
p182
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 11:07:52
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:14:24
from helper import merkle_parent_level
def merkle_root(hashes):
'''Takes a list of binary hashes and returns the merkle root
'''
# current level starts as hashes
current_level = hashes
# loop until there's exactly 1 element
while len(current_level) > 1:
# current level becomes the merkle parent level
current_level = merkle_parent_level(current_level)
# return the 1st item of the current level
return current_level[0]
hex_hashes = [
'c117ea8ec828342f4dfb0ad6bd140e03a50720ece40169ee38bdc15d9eb64cf5',
'c131474164b412e3406696da1ee20ab0fc9bf41c8f05fa8ceea7a08d672d7cc5',
'f391da6ecfeed1814efae39e7fcb3838ae0b02c02ae7d0a5848a66947c0727b0',
'3d238a92a94532b946c90e19c49351c763696cff3db400485b813aecb8a13181',
'10092f2633be5f3ce349bf9ddbde36caa3dd10dfa0ec8106bce23acbff637dae',
'7d37b3d54fa6a64869084bfd2e831309118b9e833610e6228adacdbd1b4ba161',
'8118a77e542892fe15ae3fc771a4abfd2f5d5d5997544c3487ac36b5c85170fc',
'dff6879848c2c9b62fe652720b8df5272093acfaa45a43cdb3696fe2466a3877',
'b825c0745f46ac58f7d3759e6dc535a1fec7820377f24d4c2c6ad2cc55c0cb59',
'95513952a04bd8992721e9b7e2937f1c04ba31e0469fbe615a78197f68f52b7c',
'2e6d722e5e4dbdf2447ddecc9f7dabb8e299bae921c99ad5b0184cd9eb8e5908',
'b13a750047bc0bdceb2473e5fe488c2596d7a7124b4e716fdd29b046ef99bbf0',
]
hashes = [bytes.fromhex(x) for x in hex_hashes]
root = merkle_root(hashes)
print(root.hex())
测试
acbcab8bcc1af95d8d563b77d24c3d19b18f1486383d75a5085c4e86c86beed6
[Finished in 399ms]
练习4
p183
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 11:20:26
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:20:26
class Block:
...
def validate_merkle_root(self):
'''Gets the merkle root of the tx_hashes and checks that it's
the same as the merkle root of this block.
'''
# reverse each item in self.tx_hashes
hashes = [h[::-1] for h in self.tx_hashes]
# compute the Merkle Root and reverse
root = merkle_root(hashes)
# return whether self.merkle_root is the same
return root[::-1] == self.merkle_root
运行结果
无
练习5
p187
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 11:24:09
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:26:48
import math
total = 27
max_depth = math.ceil(math.log(total, 2))
merkle_tree = []
for depth in range(max_depth + 1):
num_itmes = math.ceil(total / 2 ** (max_depth - depth))
level_hashes = [None] * num_itmes
merkle_tree.append(level_hashes)
for level in merkle_tree:
print(level)
运行结果
[None]
[None, None]
[None, None, None, None]
[None, None, None, None, None, None, None]
[None, None, None, None, None, None, None, None, None, None, None, None, None, None]
[None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]
[Finished in 397ms]
练习6
p193
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 11:38:42
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:39:00
class MerkleTree:
...
@classmethod
def parse(cls, s):
'''Takes a byte stream and parses a merkle block. Returns a Merkle Block object'''
# version - 4 bytes, Little-Endian integer
version = little_endian_to_int(s.read(4))
# prev_block - 32 bytes, Little-Endian (use [::-1])
prev_block = s.read(32)[::-1]
# merkle_root - 32 bytes, Little-Endian (use [::-1])
merkle_root = s.read(32)[::-1]
# timestamp - 4 bytes, Little-Endian integer
timestamp = little_endian_to_int(s.read(4))
# bits - 4 bytes
bits = s.read(4)
# nonce - 4 bytes
nonce = s.read(4)
# total transactions in block - 4 bytes, Little-Endian integer
total = little_endian_to_int(s.read(4))
# number of transaction hashes - varint
num_hashes = read_varint(s)
hashes = []
# each transaction is 32 bytes, Little-Endian
for _ in range(num_hashes):
hashes.append(s.read(32)[::-1])
# length of flags field - varint
flags_length = read_varint(s)
# read the flags field
flags = s.read(flags_length)
# initialize class
return cls(version, prev_block, merkle_root, timestamp, bits, nonce, total, hashes, flags)
运行结果
无
练习7
p197
代码实现
# -*- coding: utf-8 -*-
# @Author: 从化北(喵星人)
# @Date: 2022-01-16 11:45:26
# @Last Modified by: 从化北
# @Last Modified time: 2022-01-16 11:45:26
class MerkleBlock:
...
def is_valid(self):
'''Verifies whether the merkle tree information validates to the merkle root'''
# convert the flags field to a bit field
flag_bits = bytes_to_bit_field(self.flags)
# reverse self.hashes for the merkle root calculation
hashes = [h[::-1] for h in self.hashes]
# initialize the merkle tree
merkle_tree = MerkleTree(self.total)
# populate the tree with flag bits and hashes
merkle_tree.populate_tree(flag_bits, hashes)
# check if the computed root reversed is the same as the merkle root
return merkle_tree.root()[::-1] == self.merkle_root
运行结果
无
标签：None,parent,level,第十一章,编程,merkle,hashes,区块,root 来源： https://blog.csdn.net/qq_42182429/article/details/122520339