A Linear time algorithm for deciding security

The Folklore is replete with stories of "secure" protection systems being compromised in a matter of hours. This is quite astounding since one is not likely to claim that a system is secure without some sort of proof to support the claim. In practice, proof is not provided and one reason for this is clear: although the protection primitives are apparently quite simple, they may potentially interact in extremely complex ways. Vague and informal arguments, therefore, often overlook subtleties that an adversary can exploit. Precision is not merely desirable for protection systems, it is mandatory.