src/test/hs_indexes.py

   1 #
   2 # The hidden service subsystem has two type of index. The first type is a
   3 # value that each node in the network gets assigned to using their identity
   4 # key which is their position in the hashring. (hs_build_hsdir_index()).
   5 #
   6 # The second type is a value that both the client and service computes to
   7 # store/fetch the descriptor on the hashring. (hs_build_hs_index()).
   8 #
   9
  10 # Future imports for Python 2.7, mandatory in 3.0
  11 from __future__ import division
  12 from __future__ import print_function
  13 from __future__ import unicode_literals
  14
  15 import sys
  16 import hashlib
  17 import struct
  18 import base64
  19
  20 # Python 3.6+, the SHA3 is available in hashlib natively. Else this requires
  21 # the pysha3 package (pip install pysha3).
  22 if sys.version_info < (3, 6):
  23     import sha3
  24     # Test vector to make sure the right sha3 version will be used. pysha3 < 1.0
  25     # used the old Keccak implementation. During the finalization of SHA3, NIST
  26     # changed the delimiter suffix from 0x01 to 0x06. The Keccak sponge function
  27     # stayed the same. pysha3 1.0 provides the previous Keccak hash, too.
  28     TEST_VALUE = "e167f68d6563d75bb25f3aa49c29ef612d41352dc00606de7cbd630bb2665f51"
  29     if TEST_VALUE != sha3.sha3_256(b"Hello World").hexdigest():
  30         print("pysha3 version is < 1.0. Please install from:")
  31         print("https://github.com/tiran/pysha3https://github.com/tiran/pysha3")
  32         sys.exit(1)
  33
  34 # The first index we'll build is the position index in the hashring that is
  35 # constructed by the hs_build_hsdir_index() function. Construction is:
  36 #   SHA3-256("node-idx" | node_identity |
  37 #            shared_random_value | INT_8(period_length) | INT_8(period_num) )
  38
  39 PREFIX = "node-idx".encode()
  40 # 32 bytes ed25519 pubkey.
  41 IDENTITY = ("\x42" * 32).encode()
  42 # SRV is 32 bytes.
  43 SRV = ("\x43" * 32).encode()
  44 # Time period length is a 8 bytes value.
  45 PERIOD_LEN = 1440
  46 # Period number is a 8 bytes value.
  47 PERIOD_NUM = 42
  48
  49 data = struct.pack('!8s32s32sQQ', PREFIX, IDENTITY, SRV, PERIOD_NUM,
  50                                   PERIOD_LEN)
  51 hsdir_index = hashlib.sha3_256(data).hexdigest()
  52
  53 print("[hs_build_hsdir_index] %s" % (hsdir_index))
  54
  55 # The second index we'll build is where the HS stores and the client fetches
  56 # the descriptor on the hashring. It is constructed by the hs_build_hs_index()
  57 # function and the construction is:
  58 #   SHA3-256("store-at-idx" | blinded_public_key |
  59 #            INT_8(replicanum) | INT_8(period_num) | INT_8(period_length) )
  60
  61 PREFIX = "store-at-idx".encode()
  62 # 32 bytes ed25519 pubkey.
  63 PUBKEY = ("\x42" * 32).encode()
  64 # Replica number is a 8 bytes value.
  65 REPLICA_NUM = 1
  66 # Time period length is a 8 bytes value.
  67 PERIOD_LEN = 1440
  68 # Period number is a 8 bytes value.
  69 PERIOD_NUM = 42
  70
  71 data = struct.pack('!12s32sQQQ', PREFIX, PUBKEY, REPLICA_NUM, PERIOD_LEN,
  72                                    PERIOD_NUM)
  73 hs_index = hashlib.sha3_256(data).hexdigest()
  74
  75 print("[hs_build_hs_index]   %s" % (hs_index))