34 lines
843 B
Python
34 lines
843 B
Python
try:
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from hashlib import blake2s
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except:
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from pyblake2 import blake2s
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blake = lambda x: blake2s(x).digest()
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def merkelize(L):
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nodes = [b''] * len(L) + [x.to_bytes(32, 'big') if isinstance(x, int) else x for x in L]
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for i in range(len(L) - 1, 0, -1):
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nodes[i] = blake(nodes[i*2] + nodes[i*2+1])
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return nodes
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def mk_branch(tree, index):
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index += len(tree) // 2
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o = [tree[index]]
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while index > 1:
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o.append(tree[index ^ 1])
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index //= 2
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return o
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def verify_branch(root, index, proof, output_as_int=False):
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index += 2**len(proof)
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v = proof[0]
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for p in proof[1:]:
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if index % 2:
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v = blake(p + v)
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else:
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v = blake(v + p)
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index //= 2
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assert v == root
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return int.from_bytes(proof[0], 'big') if output_as_int else proof[0]
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