63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
import base64
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import hashlib
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from typing import Tuple
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from Crypto.Cipher import AES
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BLOCK_SIZE = 32 # PKCS5/PKCS7 padding 使用 32 字节块大小
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def pkcs5_unpadding(data: bytes) -> bytes:
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pad = data[-1]
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if pad < 1 or pad > 32:
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return data
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return data[:-pad]
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def pkcs5_padding(data: bytes) -> bytes:
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amount_to_pad = BLOCK_SIZE - (len(data) % BLOCK_SIZE)
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return data + bytes([amount_to_pad]) * amount_to_pad
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def get_aes_key_and_iv(encoding_aes_key: str) -> Tuple[bytes, bytes]:
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"""
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encoding_aes_key 是平台给的 43 位字符串，需要先补一个 '=' 再 base64 解码。
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得到 32 字节 key，前 16 字节为 iv。
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"""
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aes_key = base64.b64decode(encoding_aes_key + "=")
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if len(aes_key) != 32:
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raise ValueError("encodingAESKey 无效，解码后长度不是 32 字节")
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iv = aes_key[:16]
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return aes_key, iv
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def aes_decrypt_base64(cipher_b64: str, encoding_aes_key: str) -> str:
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aes_key, iv = get_aes_key_and_iv(encoding_aes_key)
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cipher_bytes = base64.b64decode(cipher_b64)
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cipher = AES.new(aes_key, AES.MODE_CBC, iv)
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decrypted = cipher.decrypt(cipher_bytes)
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decrypted = pkcs5_unpadding(decrypted)
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return decrypted.decode("utf-8")
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def aes_encrypt_base64(plaintext: str, encoding_aes_key: str) -> str:
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aes_key, iv = get_aes_key_and_iv(encoding_aes_key)
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data = plaintext.encode("utf-8")
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padded = pkcs5_padding(data)
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cipher = AES.new(aes_key, AES.MODE_CBC, iv)
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encrypted = cipher.encrypt(padded)
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return base64.b64encode(encrypted).decode("utf-8")
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def calc_signature(token: str, timestamp: int, skill_name: str, intent_name: str, query: str) -> str:
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"""
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文档签名算法：
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str = token + time.Now.Unix + skill_name + intent_name + query
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signature = MD5(str) 小写 hex
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参考：https://developers.weixin.qq.com/doc/aispeech/confapi/thirdapi/thirdapi.html
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"""
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s = f"{token}{timestamp}{skill_name}{intent_name}{query}"
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return hashlib.md5(s.encode("utf-8")).hexdigest()
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