def decrypt(self, id, data):
if data[0] != self.TYPE:
raise IntegrityError('Invalid encryption envelope')
data = zlib.decompress(memoryview(data)[1:])
if id and sha256(data).digest() != id:
raise IntegrityError('Chunk id verification failed')
return data
def decrypt(self, id, data):
if data[0] != self.TYPE:
raise IntegrityError('Invalid encryption envelope')
hmac = memoryview(data)[1:33]
if memoryview(HMAC(self.enc_hmac_key, memoryview(data)[33:], sha256).digest()) != hmac:
raise IntegrityError('Encryption envelope checksum mismatch')
self.dec_cipher.reset(iv=PREFIX + data[33:41])
data = zlib.decompress(self.dec_cipher.decrypt(data[41:])) # should use memoryview
if id and HMAC(self.id_key, data, sha256).digest() != id:
raise IntegrityError('Chunk id verification failed')
return data
def load(self, filename, passphrase):
with open(filename, 'r') as fd:
cdata = a2b_base64(''.join(fd.readlines()[1:]).encode('ascii')) # .encode needed for Python 3.[0-2]
data = self.decrypt_key_file(cdata, passphrase)
if data:
key = msgpack.unpackb(data)
if key[b'version'] != 1:
raise IntegrityError('Invalid key file header')
self.repository_id = key[b'repository_id']
self.enc_key = key[b'enc_key']
self.enc_hmac_key = key[b'enc_hmac_key']
self.id_key = key[b'id_key']
self.chunk_seed = key[b'chunk_seed']
self.path = filename
return True
def extract_nonce(self, payload):
if payload[0] != self.TYPE:
raise IntegrityError('Invalid encryption envelope')
nonce = bytes_to_long(payload[33:41])
return nonce
