61 lines
1.6 KiB
Python
61 lines
1.6 KiB
Python
"""
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0: type: str: 4bytesmax
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1: enc-mode: int: 0, 1, 2 (0=plaintext, 1=asymmetic, 2=symmetric).
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2. Timestamp: int
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encrypted with specified mode:
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3. signer: bytes (max 256bits)
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4. signature: bytes (max 256bits)
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5. app_metadata: JSON
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\n
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data: bytes
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"""
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from math import floor
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from time import time
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from msgpack import packb
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from kasten import exceptions
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from kasten.types import KastenPacked
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def pack(data: bytes, data_type: 'KastenDataType',
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enc_mode: 'KastenEncryptionModeID',
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signer: bytes = None, signature: bytes = None,
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app_metadata: 'KastenSerializeableDict' = None,
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timestamp: int = None
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) -> KastenPacked:
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# Ensure data type does not exceed 4 characters
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if not data_type or len(data_type) > 4:
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raise exceptions.InvalidKastenTypeLength
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# Ensure encryption mode is in [0, 100)
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try:
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enc_mode = int(enc_mode)
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except (TypeError, ValueError):
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raise exceptions.InvalidEncryptionMode
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if not enc_mode >= 0 or enc_mode >= 100:
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raise exceptions.InvalidEncryptionMode
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try:
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data = data.encode('utf8')
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except AttributeError:
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pass
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if timestamp is None:
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timestamp = floor(time())
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timestamp = int(timestamp)
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kasten_header = [data_type, enc_mode, timestamp]
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if signer:
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if signature is None:
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raise ValueError("Signer specified without signature")
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kasten_header.extend((signer, signature))
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if app_metadata is not None:
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kasten_header.append(app_metadata)
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kasten_header = packb(kasten_header) + b'\n'
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print(kasten_header + data)
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return kasten_header + data
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