Quantum non-malleability and authentication

TY - GEN

T1 - Quantum non-malleability and authentication

AU - Alagic, Gorjan

AU - Majenz, Christian

PY - 2017/1/1

Y1 - 2017/1/1

N2 - In encryption, non-malleability is a highly desirable property: it ensures that adversaries cannot manipulate the plaintext by acting on the ciphertext. In [6], Ambainis et al. gave a definition of non-malleability for the encryption of quantum data. In this work, we show that this definition is too weak, as it allows adversaries to “inject” plaintexts of their choice into the ciphertext. We give a new definition of quantum non-malleability which resolves this problem. Our definition is expressed in terms of entropic quantities, considers stronger adversaries, and does not assume secrecy. Rather, we prove that quantum non-malleability implies secrecy; this is in stark contrast to the classical setting, where the two properties are completely independent. For unitary schemes, our notion of non-malleability is equivalent to encryption with a two-design and hence also to the. Our techniques also yield new results regarding the closely-related task of quantum authentication. We show that “total authentication” (a notion recently proposed by Garg et al. [6],) can be satisfied with two-designs, a significant improvement over the eight-design construction of [18],. We also show that, under a mild adaptation of the rejection procedure, both total authentication and our notion of non-malleability yield quantum authentication as defined by Dupuis et al. [16].

AB - In encryption, non-malleability is a highly desirable property: it ensures that adversaries cannot manipulate the plaintext by acting on the ciphertext. In [6], Ambainis et al. gave a definition of non-malleability for the encryption of quantum data. In this work, we show that this definition is too weak, as it allows adversaries to “inject” plaintexts of their choice into the ciphertext. We give a new definition of quantum non-malleability which resolves this problem. Our definition is expressed in terms of entropic quantities, considers stronger adversaries, and does not assume secrecy. Rather, we prove that quantum non-malleability implies secrecy; this is in stark contrast to the classical setting, where the two properties are completely independent. For unitary schemes, our notion of non-malleability is equivalent to encryption with a two-design and hence also to the. Our techniques also yield new results regarding the closely-related task of quantum authentication. We show that “total authentication” (a notion recently proposed by Garg et al. [6],) can be satisfied with two-designs, a significant improvement over the eight-design construction of [18],. We also show that, under a mild adaptation of the rejection procedure, both total authentication and our notion of non-malleability yield quantum authentication as defined by Dupuis et al. [16].

UR - http://www.scopus.com/inward/record.url?scp=85028452335&partnerID=8YFLogxK

U2 - 10.1007/978-3-319-63715-0_11

DO - 10.1007/978-3-319-63715-0_11

M3 - Article in proceedings

AN - SCOPUS:85028452335

SN - 9783319637143

VL - 2

T3 - Lecture notes in computer science

SP - 310

EP - 341

BT - Advances in Cryptology – CRYPTO 2017 - 37th Annual International Cryptology Conference, Proceedings

A2 - Katz, Jonathan

A2 - Shacham, Hovav

PB - Springer VS

T2 - 37th Annual International Cryptology Conference, CRYPTO 2017

Y2 - 20 August 2017 through 24 August 2017

ER -