52 lines
1.8 KiB
Python
52 lines
1.8 KiB
Python
# This is a reference implementation of the COMMIT/REVEAL calculation for
|
|
# prop250. We use it to generate a test vector for the test_encoding()
|
|
# unittest.
|
|
#
|
|
# Here is the computation formula:
|
|
#
|
|
# H = SHA3-256
|
|
# TIMESTAMP = 8 bytes network-endian value
|
|
# RAND = H(32 bytes of random)
|
|
#
|
|
# REVEAL = base64-encode( TIMESTAMP || RAND )
|
|
# COMMIT = base64-encode( TIMESTAMP || H(REVEAL) )
|
|
#
|
|
|
|
import sys
|
|
import hashlib
|
|
import struct
|
|
import base64
|
|
|
|
# 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)
|
|
|
|
# TIMESTAMP
|
|
ts = 1454333590
|
|
# RAND
|
|
data = 'A' * 32 # Yes very very random, NIST grade :).
|
|
rand = hashlib.sha3_256(data)
|
|
|
|
reveal = struct.pack('!Q', ts) + rand.digest()
|
|
b64_reveal = base64.b64encode(reveal)
|
|
print("REVEAL: %s" % (b64_reveal))
|
|
|
|
# Yes we do hash the _encoded_ reveal here that is H(REVEAL)
|
|
hashed_reveal = hashlib.sha3_256(b64_reveal)
|
|
commit = struct.pack('!Q', ts) + hashed_reveal.digest()
|
|
print("COMMIT: %s" % (base64.b64encode(commit)))
|
|
|
|
# REVEAL: AAAAAFavXpZJxbwTupvaJCTeIUCQmOPxAMblc7ChL5H2nZKuGchdaA==
|
|
# COMMIT: AAAAAFavXpbkBMzMQG7aNoaGLFNpm2Wkk1ozXhuWWqL//GynltxVAg==
|