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53 lines
1.3 KiB
53 lines
1.3 KiB
6 years ago
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"""Encryption module that uses pyca/cryptography"""
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import os
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import json
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives.ciphers import (
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Cipher, algorithms, modes
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)
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def aesEncrypt(data, key):
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# Generate a random 96-bit IV.
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iv = os.urandom(12)
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# Construct an AES-GCM Cipher object with the given key and a
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# randomly generated IV.
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encryptor = Cipher(
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algorithms.AES(key),
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modes.GCM(iv),
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backend=default_backend()
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).encryptor()
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# Encrypt the plaintext and get the associated ciphertext.
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# GCM does not require padding.
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ciphertext = encryptor.update(data) + encryptor.finalize()
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return iv + encryptor.tag + ciphertext
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def aesDecrypt(data, key):
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iv = data[:12]
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tag = data[12:28]
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ciphertext = data[28:]
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# Construct a Cipher object, with the key, iv, and additionally the
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# GCM tag used for authenticating the message.
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decryptor = Cipher(
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algorithms.AES(key),
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modes.GCM(iv, tag),
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backend=default_backend()
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).decryptor()
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# Decryption gets us the authenticated plaintext.
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# If the tag does not match an InvalidTag exception will be raised.
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return decryptor.update(ciphertext) + decryptor.finalize()
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has_aes = True
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def getKeyLength():
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return 32
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