53 lines
1.6 KiB
Python
53 lines
1.6 KiB
Python
"""
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Blind signature chain with a top level CA
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"""
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from .eccblind import ECCBlind
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class ECCBlindChain(object): # pylint: disable=too-few-public-methods
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"""
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# Class for ECC Blind Chain signature functionality
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"""
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def __init__(self, ca=None, chain=None):
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self.chain = []
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self.ca = []
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if ca:
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for i in range(0, len(ca), 35):
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self.ca.append(ca[i:i + 35])
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if chain:
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self.chain.append(chain[0:35])
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for i in range(35, len(chain), 100):
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if len(chain[i:]) == 65:
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self.chain.append(chain[i:i + 65])
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else:
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self.chain.append(chain[i:i + 100])
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def verify(self, msg, value):
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"""Verify a chain provides supplied message and value"""
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parent = None
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l_ = 0
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for level in self.chain:
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l_ += 1
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pubkey = None
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signature = None
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if len(level) == 100:
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pubkey, signature = (level[0:35], level[35:])
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elif len(level) == 35:
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if level not in self.ca:
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return False
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parent = level
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continue
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else:
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signature = level
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verifier_obj = ECCBlind(pubkey=parent)
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if pubkey:
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if not verifier_obj.verify(pubkey, signature, value):
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return False
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parent = pubkey
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else:
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return verifier_obj.verify(msg=msg, signature=signature,
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value=value)
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return None
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