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* Replace pycryptodome with cryptography * Update presidio-anonymizer/presidio_anonymizer/operators/aes_cipher.py Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * Lock version, fix NOTICE * Update pyproject.toml --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
58 lines
2.0 KiB
Python
58 lines
2.0 KiB
Python
import base64
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import os
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from cryptography.hazmat.primitives import padding
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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class AESCipher:
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"""Advanced Encryption Standard (aka Rijndael) en/decryption in CBC mode."""
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@staticmethod
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def encrypt(key: bytes, text: str) -> str:
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"""
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Encrypts a text using AES cypher in CBC mode.
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Uses padding and random IV.
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:param key: AES encryption key in bytes.
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:param text: The text for encryption.
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:returns: The encrypted text.
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"""
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encoded_text = text.encode("utf-8")
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padder = padding.PKCS7(algorithms.AES.block_size).padder()
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padded_text = padder.update(encoded_text) + padder.finalize()
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iv = os.urandom(16)
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cipher = Cipher(algorithms.AES(key), modes.CBC(iv))
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encryptor = cipher.encryptor()
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encrypted_text = base64.urlsafe_b64encode(
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iv + encryptor.update(padded_text) + encryptor.finalize()
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)
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return encrypted_text.decode()
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@staticmethod
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def decrypt(key: bytes, text: str) -> str:
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"""
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Decrypts a previously AES-CBC encrypted text.
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:param key: AES encryption key in bytes.
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:param text: The text for decryption.
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:returns: The decrypted text.
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"""
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decoded_text = base64.urlsafe_b64decode(text)
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iv = decoded_text[:16]
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ct = decoded_text[16:]
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cipher = Cipher(algorithms.AES(key), modes.CBC(iv))
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decryptor = cipher.decryptor()
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unpadder = padding.PKCS7(128).unpadder()
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decrypted_text = decryptor.update(ct) + decryptor.finalize()
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return (unpadder.update(decrypted_text) + unpadder.finalize()).decode("utf-8")
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@staticmethod
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def is_valid_key_size(key: bytes) -> bool:
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"""
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Validate key size for AES.
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:param key: AES encryption key in bytes.
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:returns: True if the key is of valid size, False otherwise.
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"""
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return len(key) * 8 in algorithms.AES.key_sizes
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