28 lines
883 B
Python
28 lines
883 B
Python
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from typing import Callable, Tuple
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import Crypto.PublicKey.ECC as ECC
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from libp2p.crypto.ecc import create_new_key_pair
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from libp2p.crypto.keys import PublicKey
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SharedKeyGenerator = Callable[[bytes], bytes]
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def create_ephemeral_key_pair(curve_type: str) -> Tuple[PublicKey, SharedKeyGenerator]:
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"""
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Facilitates ECDH key exchange.
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"""
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if curve_type != "P-256":
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raise NotImplementedError()
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key_pair = create_new_key_pair(curve_type)
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def _key_exchange(serialized_remote_public_key: bytes) -> bytes:
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remote_public_key = ECC.import_key(serialized_remote_public_key)
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curve_point = remote_public_key.pointQ
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secret_point = curve_point * key_pair.private_key.impl.d
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byte_size = secret_point.size_in_bytes()
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return secret_point.x.to_bytes(byte_size, byteorder="big")
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return key_pair.public_key, _key_exchange
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