- CAS Institute of Computing Technology
- CESNET [Prague]
- CITI Centre of Innovation in Telecommunications and Integration of services
- CROCUS Technology
- CS-DISTRINET
- California Institute of Technology
- California State University [Long Beach]
- Carleton University
- Carnegie Mellon University [Pittsburgh]
- Catholic University of Leuven = Katholieke Universiteit Leuven
- Center for Advanced Security Research Darmstadt [Darmstadt]
- Center for Education and Research in Information Assurance and Security (Purdue University)
- Center for Medical Biotechnology
- Center for Research in Advanced Computing Systems
- Center for Secure Information Systems [Fairfax]
- CentraleSupélec
- Centre National de la Recherche Scientifique
- Centre for Quantifiable Quality of Service in Communication Systems
- Centre for Robotics and Neural Systems
- Centre for Security, Communications and Network Research
- Chair of Mobile Business & Multilateral Security
- Chalmers University of Technology [Gothenburg, Sweden]
- Chalmers University of Technology [Göteborg]
- Charles Sturt University [Australia]
- Chinese Academy of Sciences [Beijing]
- Chinese Academy of Sciences [Changchun Branch]
- Chonnam National University [Gwangju]
- City University of Hong Kong [Hong Kong]
- Cloud Creative Group
- College of Computer and Information Sciences [Riyadh]
- College of William and Mary [Williamsburg]
- Colorado State University [Fort Collins]
- Columbia University [New York]
- Commonwealth Scientific and Industrial Research Organisation Energy Technology
- Commonwealth Scientific and Industrial Research Organisation [Australia]
- Company Watch Ltd
- Computational Biology Center
- Computer Science Department
- Computer Science Department of University of Malaga
- Computer Science and Computer Engineering [Fayetteville]
- Computer Science and Engineering Department [NYU Tandon School of Engineering]
- Concordia University [Montreal]
- Confidentialité, Intégrité, Disponibilité et Répartition
- Construction and Analysis of Systems for Confidentiality and Authenticity of Data and Entities
- Corelight
- CyberTree Research Institute
- Czech Academy of Sciences [Prague]
- Czech Technical University in Prague