Entropically secure encryption with faster key expansion

Fuente: arXiv
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Auteurs principaux: Temel, Mehmet Huseyin, Skoric, Boris
Format: Preprint
Publié: 2022
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author Temel, Mehmet Huseyin
Skoric, Boris
author_facet Temel, Mehmet Huseyin
Skoric, Boris
contents Entropically secure encryption is a way to encrypt a large plaintext with a small key and still have information-theoretic security, thus in a certain sense circumventing Shannon's result that perfect encryption requires the key to be at least as long as the entropy of the plaintext. Entropically secure encryption is not perfect, and it works only if a lower bound is known on the entropy of the plaintext. The typical implementation is to expand the short key to the size of the plaintext, e.g. by multiplication with a public random string, and then use one-time pad encryption. This works in the classical as well as the quantum setting. In this paper, we introduce a new key expansion method that is faster than existing ones. We prove that it achieves the same security. The speed gain is most notable when the key length is a sizeable fraction of the message length. In particular, a factor of 2 is gained in the case of approximate randomization of quantum states.
format Preprint
id arxiv_https___arxiv_org_abs_2201_00188
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Entropically secure encryption with faster key expansion
Temel, Mehmet Huseyin
Skoric, Boris
Quantum Physics
Entropically secure encryption is a way to encrypt a large plaintext with a small key and still have information-theoretic security, thus in a certain sense circumventing Shannon's result that perfect encryption requires the key to be at least as long as the entropy of the plaintext. Entropically secure encryption is not perfect, and it works only if a lower bound is known on the entropy of the plaintext. The typical implementation is to expand the short key to the size of the plaintext, e.g. by multiplication with a public random string, and then use one-time pad encryption. This works in the classical as well as the quantum setting. In this paper, we introduce a new key expansion method that is faster than existing ones. We prove that it achieves the same security. The speed gain is most notable when the key length is a sizeable fraction of the message length. In particular, a factor of 2 is gained in the case of approximate randomization of quantum states.
title Entropically secure encryption with faster key expansion
topic Quantum Physics
url https://arxiv.org/abs/2201.00188