Abdulrahman Alhothaily

Certificate validation in public key infrastructure (PKI) is a vital phase of establishing secure connections on any network. There has been a great deal of speculation on how to efficiently validate digital certificates in PKI on which the security of network communications rests. Developing such a system is challenging because digital certificates need to be quickly and securely validated for a large number of clients in a short period of time at a low cost. On the other hand, our analysis on the TLS handshakes of the Alexa Top 1 Million domains dataset indicates that the current popular certificate validation systems cannot deliver certificate validation information to the clients in a timely fashion and suffer from high overhead at the client side, making them susceptible to a number of attacks. Motivated by these observations, we present SecureGuard, a certificate validation system that can effectively handle certificate validation during TLS handshakes. Our system utilizes Internet service providers (ISPs) as the primary entity for certificate validation exploiting the fact that any Internet access request must pass through the ISP proxy-cache servers. We provide an extensive evaluation on SecureGuard and illustrate its efficiency. Moreover, we introduce a quantitative analysis method that can investigate the costs incurred by our system and other certificate validation approaches under the same evaluation scenarios. Our implementation results demonstrate that SecureGuard is able to validate the digital certificates within a short period of time, in a secure manner, with less network overhead.

Authentication plays a critical role in securing any online banking system, and many banks and various services have long relied on username/password combos to verify users. Memorizing usernames and passwords for a lot of accounts becomes a cumbersome and inefficient task. Furthermore, legacy authentication methods have failed over and over, and they are not immune against a wide variety of attacks that can be launched against users, networks, or authentication servers. Over the years, data breach reports emphasize that attackers have created numerous high-tech techniques to steal users' credentials, which can pose a serious threat. In this paper, we propose an efficient and practical user authentication scheme using personal devices that utilize different cryptographic primitives, such as encryption, digital signature, and hashing. The technique benefits from the widespread usage of ubiquitous computing and various intelligent portable and wearable devices that can enable users to execute a secure authentication protocol. Our proposed scheme does not require an authentication server to maintain static username and password tables for identifying and verifying the legitimacy of the login users. It not only is secure against password-related attacks, but also can resist replay attacks, shoulder-surfing attacks, phishing attacks, and data breach incidents.

Payment systems play a significant role in our daily lives. They are an important driver of economic activities and a vital part of the banking infrastructure of any country. Several current payment systems focus on security and reliability but pay less attention to users’ needs and behaviors. For example, people may share their bankcards with friends or relatives to withdraw money for various reasons. This behavior can lead to a variety of privacy and security issues since the cardholder has to share a bankcard and other sensitive information such as a personal identification number (PIN). In addition, it is commonplace that cardholders may lose their cards, and may not be able to access their accounts due to various reasons. Furthermore, transferring money to an individual who has lost their bankcard and identification information is not a straightforward task. A user-friendly person-to-person payment system is urgently needed to perform secure and reliable transactions that benefit from current technological advancements. In this paper, we propose two secure fund transfer methods termed QuickCash Online and QuickCash Offline to transfer money from peer to peer using the existing banking infrastructure. Our methods provide a convenient way to transfer money quickly, and they do not require using bank cards or any identification card. Unlike other person-to-person payment systems, the proposed methods do not require the receiving entity to have a bank account, or to perform any registration procedure. We implement our QuickCash payment systems and analyze their security strengths and properties.

Fog computing is deemed as a highly virtualized paradigm that can enable computing at the Internet of Things devices, residing in the edge of the network, for the purpose of delivering services and applications more efficiently and effectively. Since fog computing originates from and is a non-trivial extension of cloud computing, it inherits many security and privacy challenges of cloud computing, causing the extensive concerns in the research community. To enable authentic and confidential communications among a group of fog nodes, in this paper, we propose an efficient key exchange protocol based on ciphertext-policy attribute-based encryption (CP-ABE) to establish secure communications among the participants. To achieve confidentiality, authentication, verifiability, and access control, we combine CP-ABE and digital signature techniques. We analyze the efficiency of our protocol in terms of security and performance. We also implement our protocol and compare it with the certificate-based scheme to illustrate its feasibility.