mirror of
https://github.com/varun-r-mallya/py-libp2p.git
synced 2025-12-31 20:36:24 +00:00
42 lines
1.1 KiB
Python
42 lines
1.1 KiB
Python
from typing import (
|
|
Callable,
|
|
Tuple,
|
|
cast,
|
|
)
|
|
|
|
from fastecdsa.encoding import (
|
|
util,
|
|
)
|
|
|
|
from libp2p.crypto.ecc import (
|
|
ECCPrivateKey,
|
|
ECCPublicKey,
|
|
create_new_key_pair,
|
|
)
|
|
from libp2p.crypto.keys import (
|
|
PublicKey,
|
|
)
|
|
|
|
SharedKeyGenerator = Callable[[bytes], bytes]
|
|
|
|
int_bytelen = util.int_bytelen
|
|
|
|
|
|
def create_ephemeral_key_pair(curve_type: str) -> Tuple[PublicKey, SharedKeyGenerator]:
|
|
"""Facilitates ECDH key exchange."""
|
|
if curve_type != "P-256":
|
|
raise NotImplementedError()
|
|
|
|
key_pair = create_new_key_pair(curve_type)
|
|
|
|
def _key_exchange(serialized_remote_public_key: bytes) -> bytes:
|
|
private_key = cast(ECCPrivateKey, key_pair.private_key)
|
|
|
|
remote_point = ECCPublicKey.from_bytes(serialized_remote_public_key, curve_type)
|
|
secret_point = remote_point.impl * private_key.impl
|
|
secret_x_coordinate = secret_point.x
|
|
byte_size = int_bytelen(secret_x_coordinate)
|
|
return secret_x_coordinate.to_bytes(byte_size, byteorder="big")
|
|
|
|
return key_pair.public_key, _key_exchange
|