mirror of
https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-12-01 08:03:31 +01:00
77 lines
2.6 KiB
Python
77 lines
2.6 KiB
Python
# This is a reference implementation of the SRV calculation for prop250. We
|
|
# use it to generate a test vector for the test_sr_compute_srv() unittest.
|
|
# (./test shared-random/sr_compute_srv)
|
|
#
|
|
# Here is the SRV computation formula:
|
|
#
|
|
# HASHED_REVEALS = H(ID_a | R_a | ID_b | R_b | ..)
|
|
#
|
|
# SRV = SHA3-256("shared-random" | INT_8(reveal_num) | INT_4(version) |
|
|
# HASHED_REVEALS | previous_SRV)
|
|
#
|
|
|
|
# Future imports for Python 2.7, mandatory in 3.0
|
|
from __future__ import division
|
|
from __future__ import print_function
|
|
from __future__ import unicode_literals
|
|
|
|
import sys
|
|
import hashlib
|
|
import struct
|
|
|
|
# Python 3.6+, the SHA3 is available in hashlib natively. Else this requires
|
|
# the pysha3 package (pip install pysha3).
|
|
if sys.version_info < (3, 6):
|
|
import sha3
|
|
|
|
# Test vector to make sure the right sha3 version will be used. pysha3 < 1.0
|
|
# used the old Keccak implementation. During the finalization of SHA3, NIST
|
|
# changed the delimiter suffix from 0x01 to 0x06. The Keccak sponge function
|
|
# stayed the same. pysha3 1.0 provides the previous Keccak hash, too.
|
|
TEST_VALUE = "e167f68d6563d75bb25f3aa49c29ef612d41352dc00606de7cbd630bb2665f51"
|
|
if TEST_VALUE != sha3.sha3_256(b"Hello World").hexdigest():
|
|
print("pysha3 version is < 1.0. Please install from:")
|
|
print("https://github.com/tiran/pysha3https://github.com/tiran/pysha3")
|
|
sys.exit(1)
|
|
|
|
# In this example, we use three reveal values.
|
|
reveal_num = 3
|
|
version = 1
|
|
|
|
# We set directly the ascii value because memset(buf, 'A', 20) makes it to 20
|
|
# times "41" in the final string.
|
|
|
|
# Identity and reveal value of dirauth a
|
|
ID_a = 20 * "41" # RSA identity of 40 base16 bytes.
|
|
R_a = 56 * 'A' # 56 base64 characters
|
|
|
|
# Identity and reveal value of dirauth b
|
|
ID_b = 20 * "42" # RSA identity of 40 base16 bytes.
|
|
R_b = 56 * 'B' # 56 base64 characters
|
|
|
|
# Identity and reveal value of dirauth c
|
|
ID_c = 20 * "43" # RSA identity of 40 base16 bytes.
|
|
R_c = 56 * 'C' # 56 base64 characters
|
|
|
|
# Concatenate them all together and hash them to form HASHED_REVEALS.
|
|
REVEALS = (ID_a + R_a + ID_b + R_b + ID_c + R_c).encode()
|
|
hashed_reveals_object = hashlib.sha3_256(REVEALS)
|
|
hashed_reveals = hashed_reveals_object.digest()
|
|
|
|
previous_SRV = (32 * 'Z').encode()
|
|
|
|
# Now form the message.
|
|
#srv_msg = struct.pack('13sQL256ss', "shared-random", reveal_num, version,
|
|
# hashed_reveals, previous_SRV)
|
|
invariant_token = b"shared-random"
|
|
srv_msg = invariant_token + \
|
|
struct.pack('!QL', reveal_num, version) + \
|
|
hashed_reveals + \
|
|
previous_SRV
|
|
|
|
# Now calculate the HMAC
|
|
srv = hashlib.sha3_256(srv_msg)
|
|
print("%s" % srv.hexdigest().upper())
|
|
|
|
# 2A9B1D6237DAB312A40F575DA85C147663E7ED3F80E9555395F15B515C74253D
|