Paper 2022/937

Post-quantum Plaintext-awareness

Ehsan Ebrahimi, University of Luxembourg
Jeroen van Wier, University of Luxembourg

In this paper, we formalize the plaintext-awareness notion in the superposition access model in which a quantum adversary may implement the encryption oracle in a quantum device and make superposition queries to the decryption oracle. Due to various possible ways an adversary can access the decryption oracles, we present six security definitions to capture the plaintext-awareness notion with respect to each way of access. We study the relationships between these definitions and present various implications and non-implications. Classically, the strongest plaintext-awareness notion (PA2) accompanied by the indistinguishability under chosen-plaintext attack (IND-CPA) notion yields the indistinguishability under chosen-ciphertext attack (INDCCA) notion. We show that the PA2 notion is not sufficient to show the above relation when targeting the IND-qCCA notion (Boneh-Zhandry definition, Crypto 2013). However, our proposed post-quantum PA2 notion with superposition decryption queries fulfils this implication.

Available format(s)
Publication info
Published elsewhere. PQCrypto2022
Plaintext-awareness Post-quantum Security Public-key Encryption
Contact author(s)
ehsan ebrahimi @ uni lu
jeroen vanwier @ uni lu
2022-07-20: approved
2022-07-19: received
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Creative Commons Attribution-NonCommercial


      author = {Ehsan Ebrahimi and Jeroen van Wier},
      title = {Post-quantum Plaintext-awareness},
      howpublished = {Cryptology ePrint Archive, Paper 2022/937},
      year = {2022},
      note = {\url{}},
      url = {}
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