This document discusses techniques for privacy-preserving data mining, specifically geometric data perturbation techniques. It begins with an introduction to the need for privacy in data mining due to increased data collection. It then discusses different categories of data perturbation techniques, including additive noise perturbation, condensation-based perturbation, random projection perturbation, and geometric data perturbation. Geometric perturbation consists of random rotation, translation, and distance perturbations of data to preserve privacy while maintaining important geometric properties. The document concludes that geometric perturbation introduces challenges in evaluating privacy but can preserve data quality for classification models.