The Proceedings of the 21st Brazilian Symposium on Information and Computational Systems Security (SBSeg 2021) bring the papers selected and presented in the edition of the event held online in Belém-PA, during the period from October 04, 2021, to October 07, 2021. In this issue, the proceedings include 27 full papers and 04 short papers. These papers were selected through a double-blind review, from a total of 66 full papers and 11 short papers submitted, which implied an acceptance rate of 41% and 36%, respectively. The event's program committee was coordinated by Marco Amaral Henriques (Unicamp) and Eduardo Souto (UFAM), who organized this volume. The articles in this volume were submitted on July 07, 2021, accepted for publication on September 03, 2021, with the final version submitted on September 10, 2021.

The short courses presented at the event were compiled and published in an ebook. To access it, visit the SBC OpenLib book catalog.

To access the companion proceedings, visit SBSeg 2021 Companion Proceedings series.

You can find more information about SBSeg 2021 by visiting the website of the event.