IFTT-PIN: A PIN-Entry Method Leveraging the Self-Calibration Paradigm

TL;DR

IFTTPIN introduces a self-calibrating PIN-entry method that enhances security and user interaction by allowing users to choose button-to-color mappings, enabling dynamic and private PIN input.

Contribution

This paper presents a novel self-calibrating PIN-entry approach that infers user mappings without pre-assigned colors, improving security against shoulder surfing and enabling active user control.

Findings

Demonstrated online interactive IFTT-PIN with self-calibration

Showed potential for improved security against shoulder surfing

Proposed self-calibration as a new interaction paradigm

Abstract

IFTT-PIN is a self-calibrating version of the PIN-entry method introduced in Roth et al. (2004) [1]. In [1], digits are split into two sets and assigned a color respectively. To communicate their digit, users press the button with the same color that is assigned to their digit, which can thus be identified by elimination after a few iterations. IFTT-PIN uses the same principle but does not pre-assign colors to each button. Instead, users are free to choose which button to use for each color. The button-to-color mapping only exists in the user's mind and is never directly communicated to the interface. In other words, IFTT-PIN infers both the user's PIN and their preferred button-to-color mapping at the same time, a process called self-calibration. In this paper, we present online interactive demonstrations of IFTT-PIN with and without self-calibration and introduce the key concepts and assumptions making self-calibration possible. IFTT-PIN can be tested at https://jgrizou.github.io/IFTT-PIN/ with a video introduction available at https://youtu.be/5I1ibPJdLHM. We review related work in the field of brain-computer interface and further propose self-calibration as a novel approach to protect users against shoulder surfing attacks. Finally, we introduce a vault cracking challenge as a test of usability and security that was informally tested at our institute. With IFTT-PIN, we wish to demonstrate a new interactive experience where users can decide actively and on-the-fly how to use an interface. The self-calibration paradigm might lead to novel opportunities for interaction in other applications or domains. We hope this work will inspire the community to invent them.