Shamira Changeset - b9f1f39cd7af

Changeset - b9f1f39cd7af

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Laman - 5 years ago 2020-04-13 13:53:07

check for non-unique shares on joining

2 files changed with 6 insertions and 0 deletions:

src/condensed.py

src/shamira.py

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src/condensed.py

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@@ @@ -51,24 +51,27 @@ def get_constant_coef(*points): @@
 import base64
 import binascii
 class SException(Exception): pass
 def reconstruct_raw(*shares):
 	"""Tries to recover the secret from its shares.
 	:param shares: (((int) i, (bytes) share), ...)
 	:return: (bytes) reconstructed secret. Too few shares returns garbage."""
 	if len({x for (x, _) in shares}) < len(shares):
 		raise SException("Found a non-unique share. Please check your inputs.")
 	secret_len = len(shares[0][1])
 	res = [None]*secret_len
 	for i in range(secret_len):
 		points = [(x, s[i]) for (x, s) in shares]
 		res[i] = (get_constant_coef(*points))
 	return bytes(res)
 def reconstruct(*shares):
 	"""Wraps reconstruct_raw.
 	:param shares: ((str) share, ...)

src/shamira.py

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@@ @@ -31,24 +31,27 @@ def generate_raw(secret, k, n): @@
 	:param k: number of shares necessary for secret recovery. 1 <= k <= n
 	:param n: (int) number of shares generated. 1 <= n < 255
 	:return: [(i, (bytes) share), ...]"""
 	shares = [_share_byte(b, k, n) for b in secret]
 	return [(i+1, bytes([s[i] for s in shares])) for i in range(n)]
 def reconstruct_raw(*shares):
 	"""Tries to recover the secret from its shares.
 	:param shares: (((int) i, (bytes) share), ...)
 	:return: (bytes) reconstructed secret. Too few shares return garbage."""
 	if len({x for (x, _) in shares}) < len(shares):
 		raise MalformedShare("Found a non-unique share. Please check your inputs.")
 	secret_len = len(shares[0][1])
 	res = [None]*secret_len
 	for i in range(secret_len):
 		points = [(x, s[i]) for (x, s) in shares]
 		res[i] = (gf256.get_constant_coef(*points))
 	return bytes(res)
 def generate(secret, k, n, encoding="b32", label="", omit_k_n=False):
 	"""Wraps generate_raw().
 	:param secret: (str or bytes)

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