def _validate_primitive_set(pset: core.PrimitiveSet):
# TODO(juerg): also validate that there is a primary
for entries in pset.all():
for entry in entries:
if (entry.output_prefix_type != tink_pb2.RAW and
entry.output_prefix_type != tink_pb2.TINK):
raise core.TinkError('unsupported OutputPrefixType')
def __init__(self, primitive_set: core.PrimitiveSet,
ciphertext_source: BinaryIO, associated_data: bytes):
"""Create a new _DecryptingStreamWrapper.
Args:
primitive_set: The primitive set of StreamingAead primitives.
ciphertext_source: A readable file-like object from which ciphertext bytes
will be read.
associated_data: The associated data to use for decryption.
"""
super(_DecryptingStreamWrapper, self).__init__()
if not ciphertext_source.readable():
raise ValueError('ciphertext_source must be readable')
self._ciphertext_source = _rewindable_input_stream.RewindableInputStream(
ciphertext_source)
self._associated_data = associated_data
self._matching_stream = None
self._remaining_primitives = [
entry.primitive for entry in primitive_set.raw_primitives()]
self._attempting_stream = self._next_decrypting_stream()
def wrap(self, primitives_set: core.PrimitiveSet) -> prf.Prf:
if primitives_set.primary():
return primitives_set.primary().primitive
else:
return _InvalidPrf()