A secure and useful “keyless cryptosystem”

Giles Brassard

Коржик Валерий Иванович, Vladimir Starostin, K.A. Akhrameeva

We consider keyless cryptosystem proposed recently by Dean and Goldsmith. We show by simulation that this scheme is secure even so the eavesdropper uses suboptimal decoding (zero-forcing attack) with linear complexity but if the number of legitimate and eavesdropper antennas are equal to one another. But if eavesdropper has even small advantage in number of antennas, the proposed cryptosystem occurs insecure that we prove both theoretically and experimentally. We investigate a modified scheme with inverse precoder and show that it requires untractable values of the legitimate user transmitter power. Thus Dean-Goldsmith cryptosystem seems to be insecure with practical point of view.

Zvi Galil, Stuart Haber, Moti M. Yung

Коржик Валерий Иванович, Vladimir Starostin, Victor Yakovlev +3 more

The term “keyless cryptography” as it is commonly adopted, applies to secure message transmission either directly without any key distribution in advance or as key sharing protocol between communicating users, based on physical layer security, before ordinary encryption/decryption procedures. In the current chapter the results are presented concerning to keyless cryptography that have been obtained by authors recently. Firstly Shamir’s protocol of secure communication is considered where commutative encryption procedure is executed. It has been found out which of the public key algorithms can be used with such protocol. Next item of consideration concerns Dean’s and Goldsmith’s cryptosystem based on multiple-input, multiple-output (MIMO) technology. It has been established under which conditions this cryptosystem is in fact secure. The third example under consideration is EVSkey scheme proposed recently by D. Qin and Z. Ding. It has been proven that such key distribution method is in fact insecure, in spite of the authors’ claims. Our main result is a description of a key sharing protocol executing over public noiseless channels (like internet) that provides a key sharing reliability and security without any cryptographic assumptions.

Aleksandr Gerasimovich

In the current paper, some methods of information security protocols based on physical layer security are considered. It is proved that well known Shamir’s protocol can be applied to RSA cryptosystem but not to Rabin, Mac-Ellice and trellis based cryptosystems. The main stream of this paper is a description of key sharing protocol on constant public and noiseless channels (like Internet). It is shown that it is able to provide a high reliability and control of security in terms of Shannon’s information providing nothing-additional requirements to communication channels and without any cryptographic assumptions.

Senlin Liu, Dongshu Cai, Dongsheng Han +2 more