def create_summary(self):
"""
This step computes a Merkle tree over the checksums for each format
and writes a file containing the head of the tree and inclusion proofs
for each file.
"""
for fmt in self.config["formats"]:
hash_fn = self._get_hash_function(fmt)
files = [fn for fn in sorted(self.checksums)]
data = [self.checksums[fn]["hashes"][fmt] for fn in files]
tree = MerkleTree(hash_fn, data)
head = binascii.hexlify(tree.head())
proofs = [
binascii.hexlify(tree.inclusion_proof(i).to_rfc6962_bis())
for i in range(len(files))
]
summary = self._get_summary_filename(fmt)
self.info("Creating summary file: {}".format(summary))
content = "{} TREE_HEAD\n".format(head.decode('ascii'))
for i in range(len(files)):
content += "{} {}\n".format(proofs[i].decode('ascii'),
files[i])
self.write_to_file(summary, content)
def testPreComputed(self):
tree = MerkleTree(hash_fn, data)
head = tree.head()
self.assertEqual(head, nodeF)
for i in range(len(data)):
proof = tree.inclusion_proof(i)
self.assertTrue(proof.verify(hash_fn, data[i], i, len(data), head))
self.assertEqual(proof.leaf_index, i)
self.assertEqual(proof.tree_size, tree.n)
self.assertEqual(proof.path_elements, proofs[i])
def testPreComputed(self):
tree = MerkleTree(hash_fn, data)
head = tree.head()
self.assertEquals(head, nodeF)
for i in range(len(data)):
proof = tree.inclusion_proof(i)
self.assertTrue(proof.verify(hash_fn, data[i], i, len(data), head))
self.assertEquals(proof.leaf_index, i)
self.assertEquals(proof.tree_size, tree.n)
self.assertEquals(proof.path_elements, proofs[i])
def testLargeTree(self):
TEST_SIZE = 5000
ELEM_SIZE_BYTES = 16
data = [bytearray(random.getrandbits(8) for _ in xrange(ELEM_SIZE_BYTES)) for _ in xrange(TEST_SIZE)]
tree = MerkleTree(hash_fn, data)
head = tree.head()
for i in range(len(data)):
proof = tree.inclusion_proof(i)
self.assertTrue(proof.verify(hash_fn, data[i], i, len(data), head))
self.assertEquals(proof.leaf_index, i)
self.assertEquals(proof.tree_size, tree.n)
def testInclusionProofEncodeDecode(self):
tree = MerkleTree(hash_fn, data)
# Inclusion proof encode/decode round trip test
proof5 = tree.inclusion_proof(5)
serialized5 = proof5.to_rfc6962_bis()
deserialized5 = InclusionProof.from_rfc6962_bis(serialized5)
reserialized5 = deserialized5.to_rfc6962_bis()
self.assertEquals(serialized5, reserialized5)
# Inclusion proof encode known answer test
serialized5 = proof5.to_rfc6962_bis()
self.assertEquals(serialized5, known_proof5)
# Inclusion proof decode known answer test
known_deserialized5 = InclusionProof.from_rfc6962_bis(known_proof5)
self.assertEquals(proof5.leaf_index, known_deserialized5.leaf_index)
self.assertEquals(proof5.tree_size, known_deserialized5.tree_size)
self.assertEquals(proof5.path_elements, known_deserialized5.path_elements)
def create_summary(self):
"""
This step computes a Merkle tree over the checksums for each format
and writes a file containing the head of the tree and inclusion proofs
for each file.
"""
for fmt in self.config["formats"]:
hash_fn = self._get_hash_function(fmt)
files = [fn for fn in sorted(self.checksums)]
data = [self.checksums[fn]["hashes"][fmt] for fn in files]
tree = MerkleTree(hash_fn, data)
head = tree.head().encode("hex")
proofs = [tree.inclusion_proof(i).to_rfc6962_bis().encode("hex") for i in range(len(files))]
summary = self._get_summary_filename(fmt)
self.info("Creating summary file: {}".format(summary))
content = "{} TREE_HEAD\n".format(head)
for i in range(len(files)):
content += "{} {}\n".format(proofs[i], files[i])
self.write_to_file(summary, content)
