Shamira Changeset - 0c78bfbee218

Changeset - 0c78bfbee218

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Laman - 3 years ago 2022-03-03 22:36:36

compatibility with python<3.9

3 files changed with 11 insertions and 2 deletions:

src/shamira/fft.py

src/shamira/gf256.py

src/shamira/util.py

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src/shamira/fft.py

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 # GNU GPLv3, see LICENSE
 import math
 import cmath
 import itertools
 from functools import cache
 from .util import cache
 from .gf256 import gfmul, gfpow
 # divisors of 255 and their factors in natural numbers
 DIVISORS = [3, 5, 15, 17, 51, 85, 255]
 FACTORS = {3: [3], 5: [5], 15: [3, 5], 17: [17], 51: [3, 17], 85: [5, 17], 255: [3, 5, 17]}
 # values of n-th square roots in GF256
 SQUARE_ROOTS = {3: 189, 5: 12, 15: 225, 17: 53, 51: 51, 85: 15, 255: 3}
 def ceil_size(n):
 	assert n <= DIVISORS[-1]
 	for (i, ni) in enumerate(DIVISORS):

src/shamira/gf256.py

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 # GNU GPLv3, see LICENSE
 """Arithmetic operations on Galois Field 2**8. See https://en.wikipedia.org/wiki/Finite_field_arithmetic"""
-from functools import reduce, cache
 from functools import reduce
 import operator
 from .util import cache
 def _gfmul(a, b):
 	"""Basic multiplication. Russian peasant algorithm."""
 	res = 0
 	while a and b:
 		if b&1: res ^= a
 		if a&0x80: a = 0xff&(a<<1)^0x1b
 		else: a <<= 1
 		b >>= 1
 	return res

src/shamira/util.py

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@@ new file 100644 @@
 try:
 	from functools import cache
 except ImportError:  # Python<3.9
 	from functools import lru_cache
 	def cache(f):
 		return lru_cache(maxsize=None)(f)

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