On 2-switches and isomorphism classes

A 2-switch is an edge addition/deletion operation that changes adjacencies in the graph while preserving the degree of each vertex. A well known result states that graphs with the same degree sequence may be changed into each other via sequences of 2-switches. We show that if a 2-switch changes the isomorphism class of a graph, then it must take place in one of four configurations. We also present a sufficient condition for a 2-switch to change the isomorphism class of a graph. As consequences, we give a new characterization of matrogenic graphs and determine the largest hereditary graph family whose members are all the unique realizations (up to isomorphism) of their respective degree sequences.Comment: 11 pages, 6 figure

Canonical horizontal visibility graphs are uniquely determined by their degree sequence

Horizontal visibility graphs (HVGs) are graphs constructed in correspondence with number sequences that have been introduced and explored recently in the context of graph-theoretical time series analysis. In most of the cases simple measures based on the degree sequence (or functionals of these such as entropies over degree and joint degree distributions) appear to be highly informative features for automatic classification and provide nontrivial information on the associated dynam- ical process, working even better than more sophisticated topological metrics. It is thus an open question why these seemingly simple measures capture so much information. Here we prove that, under suitable conditions, there exist a bijection between the adjacency matrix of an HVG and its degree sequence, and we give an explicit construction of such bijection. As a consequence, under these conditions HVGs are unigraphs and the degree sequence fully encapsulates all the information of these graphs, thereby giving a plausible reason for its apparently unreasonable effectiveness

Spotting Fake Profiles in Social Networks via Keystroke Dynamics

Spotting and removing fake profiles could curb the menace of fake news in society. This paper, thus, investigates fake profile detection in social networks via users' typing patterns. We created a novel dataset of 468 posts from 26 users on three social networks: Facebook, Instagram, and X (previously Twitter) over six sessions. Then, we extract a series of features from keystroke timings and use them to predict whether two posts originated from the same users using three prominent statistical methods and their score-level fusion. The models' performance is evaluated under same, cross, and combined-cross-platform scenarios. We report the performance using k-rank accuracy for k varying from 1 to 5. The best-performing model obtained accuracies between 91.6-100% on Facebook (Fusion), 70.8-87.5% on Instagram (Fusion), and 75-87.5% on X (Fusion) for k from 1 to 5. Under a cross-platform scenario, the fusion model achieved mean accuracies of 79.1-91.6%, 87.5-91.6%, and 83.3-87.5% when trained on Facebook, Instagram, and Twitter posts, respectively. In combined cross-platform, which involved mixing two platforms' data for model training while testing happened on the third platform's data, the best model achieved accuracy ranges of 75-95.8% across different scenarios. The results highlight the potential of the presented method in uncovering fake profiles across social network platforms.Comment: 2024 IEEE 21st Consumer Communications \& Networking Conference (CCNC) | 9 pages, 8 figures, 3 algos

On the Inference of Soft Biometrics from Typing Patterns Collected in a Multi-device Environment

In this paper, we study the inference of gender, major/minor (computer science, non-computer science), typing style, age, and height from the typing patterns collected from 117 individuals in a multi-device environment. The inference of the first three identifiers was considered as classification tasks, while the rest as regression tasks. For classification tasks, we benchmark the performance of six classical machine learning (ML) and four deep learning (DL) classifiers. On the other hand, for regression tasks, we evaluated three ML and four DL-based regressors. The overall experiment consisted of two text-entry (free and fixed) and four device (Desktop, Tablet, Phone, and Combined) configurations. The best arrangements achieved accuracies of 96.15%, 93.02%, and 87.80% for typing style, gender, and major/minor, respectively, and mean absolute errors of 1.77 years and 2.65 inches for age and height, respectively. The results are promising considering the variety of application scenarios that we have listed in this work.Comment: The first two authors contributed equally. The code is available upon request. Please contact the last autho

USER AUTHENTICATION ACROSS DEVICES, MODALITIES AND REPRESENTATION: BEHAVIORAL BIOMETRIC METHODS

Biometrics eliminate the need for a person to remember and reproduce complex secretive information or carry additional hardware in order to authenticate oneself. Behavioral biometrics is a branch of biometrics that focuses on using a person’s behavior or way of doing a task as means of authentication. These tasks can be any common, day to day tasks like walking, sleeping, talking, typing and so on. As interactions with computers and other smart-devices like phones and tablets have become an essential part of modern life, a person’s style of interaction with them can be used as a powerful means of behavioral biometrics. In this dissertation, we present insights from the analysis of our proposed set of contextsensitive or word-specific keystroke features on desktop, tablet and phone. We show that the conventional features are not highly discriminatory on desktops and are only marginally better on hand-held devices for user identification. By using information of the context, our proposed word-specific features offer superior discrimination among users on all devices. Classifiers, built using our proposed features, perform user identification with high accuracies in range of 90% to 97%, average precision and recall values of 0.914 and 0.901 respectively. Analysis of the word-based impact factors reveal that four or five character words, words with about 50% vowels, and those that are ranked higher on the frequency lists might give better results for the extraction and use of the proposed features for user identification. We also examine a large umbrella of behavioral biometric data such as; keystroke latencies, gait and swipe data on desktop, phone and tablet for the assumption of an underlying normal distribution, which is common in many research works. Using suitable nonparametric normality tests (Lilliefors test and Shapiro-Wilk test) we show that a majority of the features from all activities and all devices, do not follow a normal distribution. In most cases less than 25% of the samples that were tested had p values \u3e 0.05. We discuss alternate solutions to address the non-normality in behavioral biometric data. Openly available datasets did not provide the wide range of modalities and activities required for our research. Therefore, we have collected and shared an open access, large benchmark dataset for behavioral biometrics on IEEEDataport. We describe the collection and analysis of our Syracuse University and Assured Information Security - Behavioral Biometrics Multi-device and multi -Activity data from Same users (SU-AIS BB-MAS) Dataset. Which is an open access dataset on IEEEdataport, with data from 117 subjects for typing (both fixed and free text), gait (walking, upstairs and downstairs) and touch on Desktop, Tablet and Phone. The dataset consists a total of about: 3.5 million keystroke events; 57.1 million data-points for accelerometer and gyroscope each; 1.7 million datapoints for swipes and is listed as one of the most popular datasets on the portal (through IEEE emails to all members on 05/13/2020 and 07/21/2020). We also show that keystroke dynamics (KD) on a desktop can be used to classify the type of activity, either benign or adversarial, that a text sample originates from. We show the inefficiencies of popular temporal features for this task. With our proposed set of 14 features we achieve high accuracies (93% to 97%) and low Type 1 and Type 2 errors (3% to 8%) in classifying text samples of different sizes. We also present exploratory research in (a) authenticating users through musical notes generated by mapping their keystroke latencies to music and (b) authenticating users through the relationship between their keystroke latencies on multiple devices