Typing Speed for Continuous Authentication on Short Messages

Authors

Christopher Njaravani, University of Pretoria, South Africa

Jan Eloff, University of Pretoria, South Africa

Published in

IST-Africa 2026 Conference Proceedings

ISSN: 2576-8581

ISBN: 978-1-905824-76-2

DOI: https://doi.org/10.67725/IST-Africa.2026.XTKL7506

Publisher

IST-Africa Institute and IIMC International Information Management Corporation Ltd

Published in Ireland

Abstract

Initial authentication methods such as PINs and passwords rely on single-point verification, leaving short messaging platforms such as WhatsApp vulnerable to unauthorised access after initial login. This study proposes a continuous authentication system based on typing speed analysis for real-time user verification in short message contexts, addressing a critical security gap in active messaging sessions. A systematic study was conducted in which participants typed short messages on an Android mobile application, with typing speed recorded across 5-character sequences. Evaluation across three participant groups (10, 17, and 34) showed consistent performance improved as the window size increased from 20 to 30 characters, achieving a True Negative Rate of 95.96% and a False Positive Rate of 4.04% for 30-character messages. As the approach relies solely on typing speed, requiring minimal computation, it is well-suited for entry-level Android devices with limited processing power and RAM, making it particularly relevant for low-income users in developing regions such as Africa.

Keywords

Short Messages, Continuous Authentication, Typing Speed, Keystroke, Mobile Security, Developing Regions

Cite this paper

C. Njaravani and J. Eloff (2026) "Typing Speed for Continuous Authentication on Short Messages", IST-Africa 2026 Conference Proceedings, Miriam Cunningham and Paul Cunningham (Eds), IST-Africa Institute and IIMC, 2026, ISSN: 2576-8581, ISBN: 978-1-905824-76-2, https://doi.org/10.67725/IST-Africa.2026.XTKL7506

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