34 lines
896 B
Python
34 lines
896 B
Python
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from hashlib import blake2b
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from .sapling.key_components import prf_expand
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from .utils import i2leosp
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class HardenedOnlyContext(object):
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def __init__(self, MKGDomain, CKDDomain):
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assert type(MKGDomain) == bytes
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assert len(MKGDomain) == 16
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assert type(CKDDomain) == bytes
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assert len(CKDDomain) == 1
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self.MKGDomain = MKGDomain
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self.CKDDomain = CKDDomain
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def MKGh(Context, IKM):
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assert type(Context) == HardenedOnlyContext
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digest = blake2b(person=Context.MKGDomain)
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digest.update(IKM)
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I = digest.digest()
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I_L = I[:32]
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I_R = I[32:]
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return (I_L, I_R)
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def CKDh(Context, sk_par, c_par, i):
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assert type(Context) == HardenedOnlyContext
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assert 0x80000000 <= i and i <= 0xFFFFFFFF
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I = prf_expand(c_par, Context.CKDDomain + sk_par + i2leosp(32, i))
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I_L = I[:32]
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I_R = I[32:]
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return (I_L, I_R)
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