It seems to me that Deneb Meketa – Flash Player Security Engineer had very nice session at Adobe MAX about Flash security. PDF file covering topics of that session is very usefull for expanding knowledge. Flash security is sensitive question as it is with all web stuff so words coming from Deneb is very precious, although many thing should be known already. Thanks!
Take a look at the PDF file: Flash Security : Why and How by Deneb Meketa
more about security is coming from Raghu post
especially interesting is Adobe guide