71 lines
2.7 KiB
Python
71 lines
2.7 KiB
Python
#
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# The hidden service subsystem has two type of index. The first type is a
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# value that each node in the network gets assigned to using their identity
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# key which is their position in the hashring. (hs_build_hsdir_index()).
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#
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# The second type is a value that both the client and service computes to
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# store/fetch the descriptor on the hashring. (hs_build_hs_index()).
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#
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import sys
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import hashlib
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import struct
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import base64
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# Python 3.6+, the SHA3 is available in hashlib natively. Else this requires
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# the pysha3 package (pip install pysha3).
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if sys.version_info < (3, 6):
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import sha3
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# Test vector to make sure the right sha3 version will be used. pysha3 < 1.0
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# used the old Keccak implementation. During the finalization of SHA3, NIST
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# changed the delimiter suffix from 0x01 to 0x06. The Keccak sponge function
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# stayed the same. pysha3 1.0 provides the previous Keccak hash, too.
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TEST_VALUE = "e167f68d6563d75bb25f3aa49c29ef612d41352dc00606de7cbd630bb2665f51"
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if TEST_VALUE != sha3.sha3_256(b"Hello World").hexdigest():
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print("pysha3 version is < 1.0. Please install from:")
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print("https://github.com/tiran/pysha3https://github.com/tiran/pysha3")
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sys.exit(1)
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# The first index we'll build is the position index in the hashring that is
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# constructed by the hs_build_hsdir_index() function. Construction is:
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# SHA3-256("node-idx" | node_identity |
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# shared_random_value | INT_8(period_length) | INT_8(period_num) )
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PREFIX = "node-idx".encode()
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# 32 bytes ed25519 pubkey.
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IDENTITY = ("\x42" * 32).encode()
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# SRV is 32 bytes.
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SRV = ("\x43" * 32).encode()
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# Time period length is a 8 bytes value.
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PERIOD_LEN = 1440
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# Period number is a 8 bytes value.
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PERIOD_NUM = 42
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data = struct.pack('!8s32s32sQQ', PREFIX, IDENTITY, SRV, PERIOD_NUM,
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PERIOD_LEN)
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hsdir_index = hashlib.sha3_256(data).hexdigest()
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print("[hs_build_hsdir_index] %s" % (hsdir_index))
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# The second index we'll build is where the HS stores and the client fetches
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# the descriptor on the hashring. It is constructed by the hs_build_hs_index()
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# function and the construction is:
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# SHA3-256("store-at-idx" | blinded_public_key |
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# INT_8(replicanum) | INT_8(period_num) | INT_8(period_length) )
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PREFIX = "store-at-idx".encode()
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# 32 bytes ed25519 pubkey.
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PUBKEY = ("\x42" * 32).encode()
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# Replica number is a 8 bytes value.
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REPLICA_NUM = 1
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# Time period length is a 8 bytes value.
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PERIOD_LEN = 1440
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# Period number is a 8 bytes value.
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PERIOD_NUM = 42
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data = struct.pack('!12s32sQQQ', PREFIX, PUBKEY, REPLICA_NUM, PERIOD_LEN,
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PERIOD_NUM)
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hs_index = hashlib.sha3_256(data).hexdigest()
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print("[hs_build_hs_index] %s" % (hs_index))
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