Following upstream libaegis 0.10.5 (874f884): the absorbing-mode unauthenticated pair is deprecated in favor of the pure keystream XOR. - stream_xor(key, nonce, data, into=None): same function encrypts and decrypts; output equals data XOR stream(key, nonce); supports in-place use via into (same buffer semantics as elsewhere). - encrypt_unauthenticated/decrypt_unauthenticated kept for the old format but now emit DeprecationWarning; removed from README (stream_xor documented under Keystream generation instead).