This directory contains CSRI Technical Report #343 entitled

Properties and Meta-Properties of Secure Composable Systems

				by 

			Heather M Hinton, 
	Department of Electrical and Computer Engineering, 
		     University of Toronto

				Abstract


     The assessment of computer security includes the verification 
     that the behaviour of a system implies these desired security 
     properties.  This verification should allow us to create 
     hierarchically complex, secure systems from the interconnection 
     of simpler, secure components without the need to re-verify 
     the composite system.  

     We know that many secure behaviours become insecure on composition 
     yet we cannot always predict why or when this will be the case. 
     We define a set of safety and progress properties that are 
     necessary for the secure behaviour of a system and are common 
     to all systems.  Knowledge of the properties of these properties 
     (their meta-properties) is required to ensure that the overall 
     system will behave as expected.   We define and examine the 
     compatibility of properties and we introduce a systematic means 
     to define and assess emergent properties.    

     These safety and progress properties, together with the knowledge of 
     their meta-properties, compatibility, and emergence, are used 
     to assess and to predict the composability of security characteristics 
     of a system.  We incorporate these characteristics and criteria 
     in a Composition Principle, providing guidelines for the assessment 
     of properties of composite systems.  The Composition Principle 
     provides a more comprehensive approach to composite system 
     security than was previously possible.  This in turn will allow 
     us to compose secure systems in a manner consistent with the 
     goals of the secure behaviour of these systems.

If you have the uncompress and tar programs, get the 343.tar.Z file.
Transfer this file in binary mode, uncompress it, un-tar it and then
print the resultant files on a PostScript printer.

If you do not have uncompress or gunzip, get the 343.ps file in 
ascii mode, and print it on a PostScript printer.  
This contains the body of the report only (approximately 140 pages).  
The appendicies for the report care in the files 343_A.ps through to 343_F.ps
(another 60 pages or so). 

For those of you who wish to use some form of Word, the files 343.rtf and 
343_App.rtf are Mac Word 5.1 Interchange Format (rtf) files.  Download and
use as usual.

If you have any problems, please contact heather@eecg.toronto.edu.