Enhancing the Security of Fiber Optical Network using Cryptography

An optical fiber is an important communication channel as it proposes a high bandwidth and less attenuation, and can be easy challenging assistances such as huge-quality data transmission and others in computer networks. The basic optical transmission system consists of three basic elements which are fiber media (transmission channel), light sources as the input (covert electric signal into optic signal) and light detector as the output (convert optic signal into electric signal). FBG is the key component in optical communication system as, dispersion compensators, filters and flatteners gain. There is need to introduce mechanism that should be capable to provide data security in less time. More over there is need to introduce energy efficient mechanism that should be capable to reduce the size of packet during data transmission. There are several problems that are faced due to attenuation in fiber optics. There is need of repeater in order to regenerate the signals. Process working principle of proposed technique that is being used enhancement of security in steganography has been discussed with process flow and result. It states how brute force and timing attack are not applicable on proposed technique.

Déjà vu: Abusing Browser Cache Headers to Identify and Track Online Users

Many browser cache attacks have been proposed in the literature to sniff the user’s browsing history. All of them rely on specific time measurements to infer if a resource is in the cache or not. Unlike the state-of-the-art, this paper reports on a novel cache-based attack that is not a timing attack but that abuses the HTTP cache-control and expires headers to extract the exact date and time when a resource was cached by the browser. The privacy implications are serious as this information can not only be utilized to detect if a website was visited by the user but it can also help build a timeline of the user’s visits. This goes beyond traditional history sniffing attacks as we can observe patterns of visit and model user’s behavior on the web. To evaluate the impact of our attack, we tested it on all major browsers and found that all of them, except the ones based on WebKit, are vulnerable to it. Since our attack requires specific HTTP headers to be present, we also crawled the Tranco Top 100K websites and identified 12, 970 of them can be detected with our approach. Among them, 1, 910 deliver resources that have expiry dates greater than 100 days, enabling long-term user tracking. Finally, we discuss possible defenses at both the browser and standard levels to prevent users from being tracked.

One Bit is All It Takes: A Devastating Timing Attack on BLISS’s Non-Constant Time Sign Flips

As one of the most efficient lattice-based signature schemes, and one of the only ones to have seen deployment beyond an academic setting (e.g., as part of the VPN software suite strongSwan), BLISS has attracted a significant amount of attention in terms of its implementation security, and side-channel vulnerabilities of several parts of its signing algorithm have been identified in previous works. In this paper, we present an even simpler timing attack against it. The bimodal Gaussian distribution that BLISS is named after is achieved using a random sign flip during signature generation, and neither the original implementation of BLISS nor strongSwan ensure that this sign flip is carried out in constant time. It is therefore possible to recover the corresponding sign through side-channel leakage (using, e.g., cache attacks or branch tracing). We show that obtaining this single bit of leakage (for a moderate number of signatures) is in fact sufficient for a full key recovery attack. The recovery is carried out using a maximum likelihood estimation on the space of parameters, which can be seen as a statistical manifold. The analysis of the attack thus reduces to the computation of the Fisher information metric.

Strengthening Sequential Side-Channel Attacks Through Change Detection

The sequential structure of some side-channel attacks makes them subject to error propagation, i.e. when an error occurs during the recovery of some part of a secret key, all the following guesses might as well be chosen randomly. We propose a methodology that strengthens sequential attacks by automatically identifying and correcting errors. The core ingredient of our methodology is a change-detection test that monitors the distribution of the distinguisher values used to reconstruct the secret key. Our methodology includes an error-correction procedure that can cope both with false positives of the change-detection test, and inaccuracies of the estimated location of the wrong key guess. The proposed methodology is general and can be included in several attacks. As meaningful examples, we conduct two different side-channel attacks against RSA-2048: an horizontal power-analysis attack based on correlation and a vertical timing attack. Our experiments show that, in all the considered cases, strengthened attacks outperforms their original counterparts and alternative solutions that are based on thresholds. In particular, strengthened attacks achieve high success rates even when the side-channel measurements are noisy or limited in number, without prohibitively increasing the computing time.