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64 lines
2.0 KiB
64 lines
2.0 KiB
import base64
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from Crypto.Hash import SHA256
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from config import config
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from entity.Letter import Letter
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from tool import PriKeyHelper, DownloadPathTool
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from tool.asymmetric import RSA
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from tool.hash import Segwit
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from tool.symmetric import SM4
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def getLetter():
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# 阻塞自身 从指定端口获取信件
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#
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# 解析信件
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letter = None
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handleLetter(letter)
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pass
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def handleLetter(letter: Letter):
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# 解析信件 确认收信人
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# 获取自身key
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pki = PriKeyHelper.getUserKey()
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if pki[1] != letter.recvPubKey:
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raise Exception("信件不属于自己")
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# 用自己的私钥解密key 获得对称加密秘钥。
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key = RSA.decrypt_message(base64.b64decode(letter.encryptKey), pki[0])
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# 根据不同的对称加密算法
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try:
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type = config.getEncryptType(letter.encryptType)
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except ValueError:
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raise ValueError("不支持的对称加密算法")
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# 进行解密fileBase64
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data = b""
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if type == config.EncryptType.SM4_ECB:
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data = base64.b64decode(SM4.decrypt_ecb(letter.fileBase64, key))
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elif type == config.EncryptType.SM4_CBC:
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data = base64.b64decode(SM4.decrypt_cbc_with_iv(letter.fileBase64, key))
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elif type == config.EncryptType.AES_ECB:
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raise NotImplementedError("未实现")
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elif type == config.EncryptType.AES_CBC:
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raise NotImplementedError("未实现")
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else:
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raise KeyError("不支持的对称加密算法")
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# 用发信人的公钥验签摘要
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result = RSA.verify_signature(data, letter.sign, letter.senderPubKey)
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if not result:
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raise Exception("签名验证失败，文件不可信")
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# 保存文件
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# 默认下载目录
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download_dir = DownloadPathTool.get_download_directory()
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with open(f"{download_dir}/{letter.fileName}", "wb") as f:
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f.write(data)
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print(f"确认收到来自 {Segwit.encodeSegwit(letter.senderPubKey.encode("utf-8"))} 的文件")
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print(f"签名验证有效，已将文件 {letter.fileName} 保存至 {download_dir} 下")
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return
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