  Uncloneable decryptors are encryption schemes (with classical plaintexts and
ciphertexts) with the added functionality of deriving uncloneable quantum
states, called decryptors, which could be used to decrypt ciphers without
knowledge of the secret key (Georgiou and Zhandry, IACR'20). We study
uncloneable decryptors in the computational setting and provide increasingly
strong security notions which extend the various indistinguishable security
notions of symmetric encryption.
  We show that CPA secure uncloneable bit decryptors could be instantiated from
a copy protection scheme (Aaronson, CCC'09) for any balanced binary function.
We introduce a new notion of flip detection security for copy protection
schemes inspired by the notions of left or right security for encryption
schemes, and show that it could be used to instantiate CPA secure uncloneable
decryptors for messages of unrestricted length.
  We then show how to strengthen the CPA security of uncloneable decryptors to
CCA2 security using strong EUF-CMA secure digital signatures. We show that our
constructions could be instantiated relative to either the quantum oracle used
in [Aar09] or the classical oracle used in (Aaronson et al., CRYPTO'21) to
instantiate copy protection schemes. Our constructions are the first to achieve
CPA or CCA2 security in the symmetric setting.
