Analysis of Y00 Protocol Under Quantum Generalization of a Fast Correlation Attack: Toward Information-Theoretic Security

Abstract

In our previous work, it was demonstrated that the attacker could not pin-down the correct keys to start the Y00 protocol with a probability of one under the assistance of unlimitedly long known-plaintext attacks and optimal quantum measurements on the attacker's quantum memory.However, there were several assumptions that the Y00 system utilized linear-feedback shift registers as pseudo-random-number generators, and a fast correlation attack was disabled by irregular mapping on the Y00 systems. This study generalizes such an attack to remove the assumptions of the previous work. The framework of the security analyses of this study reiterates two well-known results from the past: (1) Y00 systems would be cryptanalyzed when the system is not designed well; (2) the system is possibly information-theoretically secure when the system is designed well, although the attacker's confidence in the correct key increases over time but the success probability of key recovery does not reach unity in finite time; (3) the breach time of the shared keys is increasingly threatened with time. Hence, a key-refreshment procedure for the Y00 protocol is provided herein.Such security analyses are important not only in key refreshment but also in initial key agreement situations.

Effect of Nano Titanium Oxide with Different Surface Treatments on Color Stability of Red-Tinted Silicone Rubber

“…For a long time, the precise color matching of prosthesis has been concerned. However, the disadvantage of silicone rubber and pigments is that they will fade over time [ 3 ]. Some data show that in clinical use, the time for patients to request the replacement of prostheses because of color change is months to a year, and color mismatch has become the main reason for the end of the service life of prostheses.…”

Y00 quantum noise randomised cipher; theoretical and experimental background

“…Suppose that a set of measurement operators at timeslot t { M ( m, m '; t | x )} is provided that satisfies the optimality corresponding to { ρ ( m , m ', x ; t )} [36–38, 49, 50]. Then the tensor product { M ( m, m '| x )} is a set of optimal measurements corresponding to { ρ ( m , m ', x )}.…”

“…When the attacks perform measurements such as CKP or GFC attacks, the effective valiance of the noise reduces as follows, from Equations (6)–(9). The concept was already given in Refs [36–38]. $$$\sigma {(N)}^{2}\propto {\sigma }^{2}/N\to 0$$$ …”

“…The following are the reasons. The attacker uses the most likely current keys to estimate the fresh keys. In this case, the fresh key may be insecure. The attacker may have some hints about the generated keys. The above means application of Leftover‐Hash Lemma (LHL) should be carefully done [37, 52, 53]. …”

“…When the set of optimal measurements { M ( m, m '; t | x )} corresponding to { ρ ( m, m '; t| x )}, Equations (17)−(24) are satisfied. Hence, the CKP attacks with quantum memory [38] reduce GFC attacks [37]. However, an open question is how to derive { M (m, m'; t | x )} and experimentally equip.…”