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36 lines
1.3 KiB
Python
36 lines
1.3 KiB
Python
from hashlib import sha256
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from binascii import unhexlify, hexlify
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from cryptography.hazmat.primitives.ciphers.aead import AESGCM
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from pisa import logging
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# FIXME: EncryptedBlob is assuming AESGCM. A cipher field should be part of the object and the decryption should be
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# performed depending on the cipher.
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class EncryptedBlob:
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def __init__(self, data):
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self.data = data
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def decrypt(self, key):
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# master_key = H(tx_id | tx_id)
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key = unhexlify(key)
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master_key = sha256(key + key).digest()
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# The 16 MSB of the master key will serve as the AES GCM 128 secret key. The 16 LSB will serve as the IV.
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sk = master_key[:16]
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nonce = master_key[16:]
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logging.info("[Watcher] creating new blob")
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logging.info("[Watcher] master key: {}".format(hexlify(master_key).decode()))
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logging.info("[Watcher] sk: {}".format(hexlify(sk).decode()))
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logging.info("[Watcher] nonce: {}".format(hexlify(nonce).decode()))
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logging.info("[Watcher] encrypted_blob: {}".format(self.data))
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# Decrypt
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aesgcm = AESGCM(sk)
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data = unhexlify(self.data.encode())
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raw_tx = aesgcm.decrypt(nonce=nonce, data=data, associated_data=None)
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hex_raw_tx = hexlify(raw_tx).decode('utf8')
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return hex_raw_tx
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