Maliheh Shirvanian

This paper presents a comprehensive usability evaluation of HIPPO (Hidden-Password Online Password), a novel store-less password manager, compared to traditional password-only authentication methods. In the digital age, robust password management solutions are essential to mitigate cognitive burdens and enhance security. Unlike conventional store-based password managers, HIPPO dynamically generates passwords without storing them, significantly reducing the risk of data breaches. Our study involved 25 participants who performed tasks such as installation, configuration, password updating, and login using both HIPPO and traditional methods. The findings reveal that HIPPO offers significant security advantages and is perceived as more secure and trustworthy by users. While HIPPO introduces additional steps for password generation and entry, participants reported higher satisfaction and ease of use compared to traditional password-only authentication. This study highlights the trade-offs between security and usability in password management, providing valuable insights for developing more user-friendly and secure password management tools.

Establishing secure voice, video and text over Internet (VoIP) communications is a crucial task necessary to prevent eavesdropping and man-in-the-middle attacks. The traditional means of secure session establishment (e.g., those relying upon PKI or KDC) require a dedicated infrastructure and may impose unwanted trust onto third-parties. “Crypto Phones” (popular instances such as PGPfone and Zfone), in contrast, provide a purely peer-to-peer user-centric secure mechanism claiming to completely address the problem of wiretapping. The secure association mechanism in Crypto Phones is based on cryptographic protocols employing Short Authenticated Strings (SAS) validated over the voice medium. The security of Crypto Phones crucially relies on the assumption that the voice channel, over which SAS is validated, provides the properties of integrity and source authentication. In this paper, we challenge this assumption, and report on automated SAS voice imitation man-in-the-middle attacks that can compromise the security of Crypto Phones in both two-party and multi-party settings, even if users pay due diligence and even if an automated software ( voice biometrics systems) is used to detect voice manipulation. The first attack, called the short voice reordering attack, builds arbitrary SAS strings in a victim’s voice by reordering previously eavesdropped SAS strings spoken by the victim. The second attack, called the short voice morphing attack, builds arbitrary SAS strings in a victim’s voice from a few previously eavesdropped sentences (less than 3 minutes) spoken by the victim. We design and implement our attacks using off-the-shelf speech recognition/synthesis tools, and comprehensively evaluate them with respect to both manual detection (based on a user study with 30 participants) and automated detection via a speaker verification tool. The results demonstrate the effectiveness of our attacks against three prominent forms of SAS encodings: numbers, PGP word lists and Madlib sentences. These attacks can be used by a wiretapper to compromise the confidentiality and privacy of Crypto Phones voice, video and text communications (plus authenticity in case of text conversations).

Many widely used Internet messaging and calling apps, such as WhatsApp, Viber, Telegram, and Signal, have deployed an end-to-end encryption functionality. To defeat potential MITM attackers against the key exchange protocol, the approach relies on users to perform a code verification task whereby each user must compare the code (a fingerprint of the cryptographic keys) computed by her app with the one computed by the other user's app and reject the session if the two do not match. In this paper, we study the security and usability of this human-centered code verification task for a setting where the end users are remotely located, and compare it as a baseline to a less frequent scenario where the users are in close proximity. We consider several variations of the code presentation and verification methods, incorporated into representative real-world apps, including codes encoded as numbers or images, displayed on the screen, and verbally spoken by the users. We perform a human factors study in a lab setting to quantify the security and usability of these different methods. Our study results expose key weaknesses in the security and usability of the code verification methods employed in the apps. First, we show that most code verification methods offer poor security (high false accepts) and low usability (high false rejects and low user experience ratings) in the remote setting. Second, we demonstrate that, security and usability under the remote code verification setting is significantly lower than that in the proximity setting. We attribute this result to the increased cognitive overhead associated with comparing the codes across two apps on the same device (remote setting) rather than across two devices (proximity setting). Overall, our work serves to highlight a serious vulnerability of Internet-based communication apps in the remote setting stemming from human errors.