Presentation given at the SWIM Seminar (University of Tsukuba) about the paper "Realizing Fine-Grained and Flexible Access Control to Outsourced Data with Attribute-Based Cryptosystems"*. This presentation is based on the uploader's understanding of the paper and may contain inaccurate interpretations. A summary of the paper is available at: https://mshcruz.wordpress.com/2016/07/22/summary-fine-grained-access-control-using-abe-and-abs/ *Zhao et al.: "Realizing Fine-Grained and Flexible Access Control to Outsourced Data with Attribute-Based Cryptosystems". ISPEC 2011.