# Preventing Shoulder-Surfing Attacks using Digraph Substitution Rules and Pass-Image Output Feedback

> Research article (Symmetry, 2019) · cited 11× · AI/ML

**Wikidata**: [openalex:W2970690440](https://www.wikidata.org/wiki/openalex:W2970690440)  
**Source**: https://4ort.xyz/entity/preventing-shoulder-surfing-attacks-using-digraph-substitution-rules-and-pass-image-output-feedback