67 lines
1.9 KiB
Python
67 lines
1.9 KiB
Python
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from __future__ import annotations
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from dataclasses import dataclass
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from typing import List, TypeAlias
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from cryptography.hazmat.primitives.asymmetric.x25519 import (
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X25519PrivateKey,
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X25519PublicKey,
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)
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from mixnet.bls import BlsPrivateKey, BlsPublicKey
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from mixnet.fisheryates import FisherYates
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NodeId: TypeAlias = BlsPublicKey
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# 32-byte that represents an IP address and a port of a mix node.
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NodeAddress: TypeAlias = bytes
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@dataclass
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class Mixnet:
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mix_nodes: List[MixNode]
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# Build a new topology deterministically using an entropy.
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# The entropy is expected to be injected from outside.
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#
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# TODO: Implement constructing a new topology in advance to minimize the topology transition time.
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# https://www.notion.so/Mixnet-Specification-807b624444a54a4b88afa1cc80e100c2?pvs=4#9a7f6089e210454bb11fe1c10fceff68
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def build_topology(
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self,
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entropy: bytes,
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n_layers: int,
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n_nodes_per_layer: int,
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) -> MixnetTopology:
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num_nodes = n_nodes_per_layer * n_layers
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assert num_nodes < len(self.mix_nodes)
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shuffled = FisherYates.shuffle(self.mix_nodes, entropy)
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sampled = shuffled[:num_nodes]
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layers = []
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for l in range(n_layers):
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start = l * n_nodes_per_layer
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layer = sampled[start : start + n_nodes_per_layer]
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layers.append(layer)
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return MixnetTopology(layers)
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@dataclass
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class MixNode:
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identity_public_key: BlsPublicKey
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encryption_public_key: X25519PublicKey
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addr: NodeAddress
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def __init__(
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self,
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identity_private_key: BlsPrivateKey,
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encryption_private_key: X25519PrivateKey,
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addr: NodeAddress,
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):
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self.identity_public_key = identity_private_key.get_g1()
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self.encryption_public_key = encryption_private_key.public_key()
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self.addr = addr
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@dataclass
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class MixnetTopology:
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layers: List[List[MixNode]]
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