Cryptology ePrint Archive: Report 2020/877

Unclonable Decryption Keys

Marios Georgiou and Mark Zhandry

Abstract: We initiate the study of encryption schemes where the decryption keys are unclonable quantum objects, which we call single decryptor encryption. We give a number of initial results in this area:

-We formalize the notion of single decryptor encryption. -We show that secret-key single decryptor encryption is possible unconditionally, in the setting where a limited number of ciphertexts are given. However, given an encryption oracle, we show that unconditional security is impossible. -We show how to use a very recent notion of one-shot signatures, together with sufficiently powerful witness encryption, to achieve public key single decryptor encryption. -We demonstrate several extensions of our scheme, achieving a number of interesting properties that are not possible classically.

Category / Keywords: foundations / Quantum Decryption Keys, Unclonable Decryption

Date: received 11 Jul 2020, last revised 29 Jul 2020

Contact author: mgeorgiou at gradcenter cuny edu, mzhandry@princeton edu

Available format(s): PDF | BibTeX Citation

Note: Corrected key naming for definitions of single decryptor encryption with dishonestly generated keys.

Version: 20200729:223034 (All versions of this report)

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