Limitations on information-theoretically-secure quantum homomorphic encryption

Homomorphic encryption is a form of encryption which allows computation to be carried out on the encrypted data without the need for decryption. The success of quantum approaches to related tasks in a delegated computation setting has raised the question of whether quantum mechanics may be used to achieve information-theoretically-secure fully homomorphic encryption. Here we show, via an information localization argument, that deterministic fully homomorphic encryption necessarily incurs exponential overhead if perfect security is required

Mutant Differential Fault Analysis of Trivium MDFA

Abstract. In this paper we present improvements to the differential fault analysis (DFA) of the stream cipher Trivium proposed in the work of M. Hojśık and B. Rudolf. In particular, we optimize the algebraic rep-resentation of obtained DFA information applying the concept of Mu-tants, which represent low degree equations derived after processing of DFA information. As a result, we are able to minimize the number of fault injections necessary for retrieving the secret key. Therefore, we in-troduce a new algebraic framework that combines the power of different algebraic techniques for handling additional information received from a physical attack. Using this framework, we are able to recover the secret key by only an one-bit fault injection. In fact, this is the first attack on stream ciphers utilizing minimal amount of DFA information. We study the efficiency of our improved attack by comparing the size of gathered DFA information with previous attacks

University of Wollongong Research Online

Fault analysis of the KATAN family of bloc