70 lines
2.1 KiB
Python
70 lines
2.1 KiB
Python
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from __future__ import annotations
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import base64
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import hashlib
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import struct
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import socket
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import time
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.hazmat.primitives import padding as sym_padding
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def verify_signature(token: str, timestamp: str, nonce: str, signature: str) -> bool:
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params = sorted([token, timestamp, nonce])
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sha1 = hashlib.sha1("".join(params).encode()).hexdigest()
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return sha1 == signature
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def decrypt_message(
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encrypted_msg: str,
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encoding_aes_key: str,
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) -> tuple[str, str]:
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key = base64.b64decode(encoding_aes_key + "=")
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ciphertext = base64.b64decode(encrypted_msg)
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cipher = Cipher(algorithms.AES(key), modes.CBC(key[:16]))
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decryptor = cipher.decryptor()
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plaintext = decryptor.update(ciphertext) + decryptor.finalize()
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pad = plaintext[-1]
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plaintext = plaintext[:-pad]
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content_len = socket.ntohl(struct.unpack("I", plaintext[16:20])[0])
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content = plaintext[20 : 20 + content_len].decode("utf-8")
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receive_id = plaintext[20 + content_len :].decode("utf-8")
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return content, receive_id
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def encrypt_message(
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content: str,
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encoding_aes_key: str,
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app_id: str,
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) -> str:
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key = base64.b64decode(encoding_aes_key + "=")
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random_bytes = struct.pack("I", int(time.time()))
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content_bytes = content.encode("utf-8")
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app_id_bytes = app_id.encode("utf-8")
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msg_len = struct.pack("!I", len(content_bytes))
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raw = random_bytes + msg_len + content_bytes + app_id_bytes
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padder = sym_padding.PKCS7(128).padder()
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padded = padder.update(raw) + padder.finalize()
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cipher = Cipher(algorithms.AES(key), modes.CBC(key[:16]))
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encryptor = cipher.encryptor()
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ciphertext = encryptor.update(padded) + encryptor.finalize()
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return base64.b64encode(ciphertext).decode()
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def verify_url_signature(token: str, timestamp: str, nonce: str, echostr: str, signature: str) -> tuple[bool, str]:
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if not verify_signature(token, timestamp, nonce, signature):
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return False, ""
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key = base64.b64decode(echostr)
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return True, key.decode("utf-8")
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