lou
37 lines
1.2 KiB
Python
37 lines
1.2 KiB
Python
"""
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解包器模块 (unpacker)
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模块: 服务端 / 解包器
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输入: 完整密文文件
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输出: 密文主体 + 加密参数
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cobblestone (C2SP chunked-encryption) 密文流自带头部+分块结构,
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解包退化为前置结构检查: 非空 + 头部长度合法。真正的完整性由 decrypt 块级认证保证。
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"""
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from pathlib import Path
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from task_manager import TaskManager
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# cobblestone 头部最小长度 (magic + 版本 + 随机 nonce 等)
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MIN_HEADER = 32
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class UnpackError(RuntimeError):
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"""密文包结构异常"""
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class Unpacker:
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def __init__(self, tasks: TaskManager) -> None:
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self.tasks = tasks
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def unpack(self, transfer_id: str, merged_path: Path) -> tuple[Path, dict]:
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"""验证密文包结构, 返回 (密文路径, 加密参数)"""
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transfer = self.tasks.get(transfer_id)
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if transfer is None:
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raise UnpackError(f"任务不存在: {transfer_id}")
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size = merged_path.stat().st_size
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if size < MIN_HEADER:
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raise UnpackError(f"密文包过短 ({size}B < {MIN_HEADER}B), 结构损坏")
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enc_params = dict(transfer["enc_params"])
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return merged_path, enc_params
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